Form 8-K

8-K — OLD SECOND BANCORP INC

Accession: 0000357173-26-000057

Filed: 2026-10-21

Period: 2026-10-21

CIK: 0000357173

SIC: 6022 (STATE COMMERCIAL BANKS)

Item: Results of Operations and Financial Condition

Item: Financial Statements and Exhibits

Documents

8-K — osbc-20261021x8k.htm (Primary)

EX-99.1 (osbc-ex99d1.htm)

EX-99.2 (osbc-ex99d2.htm)

GRAPHIC (osbc-20261021x8k001.jpg)

GRAPHIC (osbc-ex99d1001.jpg)

GRAPHIC (osbc-ex99d2g001.jpg)

GRAPHIC (osbc-ex99d2g002.jpg)

GRAPHIC (osbc-ex99d2g003.jpg)

GRAPHIC (osbc-ex99d2g004.jpg)

GRAPHIC (osbc-ex99d2g005.jpg)

GRAPHIC (osbc-ex99d2g006.jpg)

GRAPHIC (osbc-ex99d2g007.jpg)

GRAPHIC (osbc-ex99d2g008.jpg)

GRAPHIC (osbc-ex99d2g009.jpg)

GRAPHIC (osbc-ex99d2g010.jpg)

XML — IDEA: XBRL DOCUMENT (R1.htm)

8-K

8-K (Primary)

Filename: osbc-20261021x8k.htm · Sequence: 1

OLD SECOND BANCORP INC_October 21, 2026

OLD SECOND BANCORP INC0000357173false00003571732026-10-212026-10-21

United States

Securities And Exchange Commission

Washington, D.C. 20549

FORM 8-K

Current Report

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 21, 2026

(Exact name of registrant as specified in its charter)

Delaware

000-10537

36-3143493

(State or other jurisdiction of incorporation)

(Commission File Number)

(I.R.S. Employer Identification No.)

37 South River Street

Aurora, Illinois 60507

(Address of principal executive offices) (Zip code)

(630) 892-0202

(Registrant’s telephone number, including area code)

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock

OSBC

The Nasdaq Stock Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 under the Securities Act (17 CFR 230.405) or Rule 12b-2 under the Exchange Act (17 CFR 240.12b-2).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition

On October 21, 2026, Old Second Bancorp, Inc. (the “Company’s”) issued a press release announcing its financial results for the third quarter ended September 30, 2026, along with certain other financial information. Copies of the Company’s press release and loan portfolio disclosures are attached as Exhibits 99.1 and 99.2, respectively.

Item 9.01 Financial Statements and Exhibits

Exhibit No.

Description

99.1

Press Release of Old Second Bancorp, Inc. dated October 21, 2026

99.2

Loan Portfolio Disclosures for Old Second Bancorp, Inc. dated September 30, 2026

104

Cover Page Interactive Data File (the cover page XBRL tags are embedded within the Inline XBRL document)

Signature

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

OLD SECOND BANCORP, INC.

Dated: October 21, 2026

By:

/s/ Bradley S. Adams

Bradley S. Adams

Executive Vice President,

Chief Operating Officer and

Chief Financial Officer

EX-99.1

Filename: osbc-ex99d1.htm · Sequence: 2

Old Second Bancorp, Inc

(NASDAQ:OSBC)

Exhibit 99.1

Contact:

Bradley S. Adams

For Immediate Release

Chief Financial Officer

October 21, 2026

(630) 906-5484

Old Second Bancorp, Inc. Reports Third Quarter 2026 Net Income of $28.9 Million,

or $0.56 per Diluted Share

AURORA, IL, October 21, 2026 – Old Second Bancorp, Inc. (the “Company,” “Old Second,” “we,” “us,” and “our”) (NASDAQ: OSBC), the parent company of Old Second National Bank (the “Bank”), today announced financial results for the third quarter of 2026. Our net income was $28.9 million, or $0.56 per diluted share, for the third quarter of 2026, compared to net income of $28.2 million, or $0.54 per diluted share, for the second quarter of 2026. Adjusted net income1 was $28.5 million, or adjusted diluted earnings per share1 of $0.55, for the third quarter of 2026, compared to adjusted net income1 of $28.7 million, or adjusted diluted earnings per share1 of $0.55, for the second quarter of 2026.

Notable Items2

● Net interest and dividend income was $84.0 million, reflecting an increase of $720,000, or 0.86%.

● Net interest margin (NIM) on a fully tax-equivalent basis1 was 5.27%, an increase of four basis points.

● Provision for credit losses of $6.8 million compared to $7.5 million, a decrease of $750,000.

● Noninterest income was $13.1 million, a decrease of $191,000, or 1.44%, compared to $13.3 million.

● Noninterest expense was $51.6 million, an increase of $370,000, or 0.72%, compared to $51.3 million.

● Efficiency ratio increased 62 basis points to 52.34%; adjusted efficiency ratio was 52.06%1.

● Provision for income tax of $9.8 million, compared to $9.7 million, with an effective tax rate of 25.31% and 25.53%, respectively.

● Return on average assets of 1.69%, compared to 1.65%.

● Return on average tangible common equity (ROATCE)1 of 15.77%; adjusted ROATCE1 of 15.53%.

● On October 20, 2026, our Board of Directors declared a cash dividend of $0.08 per share of common stock, payable on November 9, 2026, to stockholders of record as of October 30, 2026.

Chairman, President and Chief Executive Officer Jim Eccher said, “Old Second reported strong results in the third quarter of 2026 led by robust margin performance and disciplined operating efficiency. Loan losses remained higher than we wanted this quarter due to one previously identified commercial relationship, but the trends are extremely encouraging with nonperforming and classified loans declining by 30% and 44%, respectively. Criticized loans, an early indicator of future credit trends, also improved significantly during the quarter and now stand at just 1.88% of total loans, compared to 3.05% last quarter. Criticized assets also declined significantly quarter over quarter, decreasing to 1.91% of total loans from 3.08% in the previous quarter. Profitability remains excellent with the tax-equivalent net interest margin increasing by four basis points this quarter to 5.27%, which demonstrates the benefits of a strong core deposit base and diversified loan portfolio. This level of performance and a strong capital position afforded Old Second the opportunity to repurchase 1.5 million common shares this quarter, or approximately 3% of all outstanding shares. Third quarter return on average assets and return on average tangible common equity were 1.69% and 15.77%, respectively, and the efficiency ratio was a very healthy 52.34%. Based on the strength of the balance sheet and income statement trends, Old Second elected in this fourth quarter to increase the common dividend by 14%, as we continue to regularly deliver dividend growth commensurate with the bank’s performance. We are proud of our performance for the quarter, believe we have turned the corner on credit and look forward to delivering solid results to our stockholders for the remainder of the year.”

1 Non-GAAP financial measure that management believes is useful in evaluating the financial results of the Company – refer to the non-GAAP reconciliation contained in this release.

2 All comparisons throughout this release are on a linked-quarter basis, unless otherwise noted.

Results of Operations:

Our net income was $28.9 million, or $0.56 per diluted share, for the third quarter of 2026, compared to net income of $28.2 million, or $0.54 per diluted share.

Net Interest Margin continued to be strong and nominal increases in the cost of funds were outweighed by stronger yields on loans during the quarter.

● Net interest margin on a fully tax-equivalent1 basis improved four basis points, to 5.27%.

● Loan yields increased three basis points on higher average loan balances during the quarter but investment yields decreased five basis points driven by maturities and paydowns of securities.

● Cost of funds increased two basis points to 1.23%, driven by higher costs on deposits, discussed below, as well as other short-term borrowings due to higher average FHLB overnight borrowings.

Noninterest Income decreased $191,000, or 1.44%, in the third quarter of 2026.

● Mortgage banking income increased in the period mainly due to $623,000 of mortgage servicing rights (“MSR”) mark to market gains compared to $152,000 of losses in the previous quarter, primarily the result of increased rates during the quarter.

● The cash surrender value of BOLI decreased $673,000 in the current quarter primarily due to market rate changes impacting company-owned life insurance, which is included within the same line item.

Noninterest Expense increased $370,000, or 0.72%.

● Salaries and employee benefits increased $743,000, driven by higher salaries, officer incentive accruals, and employee insurance premiums, partially offset by decreases in payroll taxes and deferred compensation expense due to market interest rate changes.

● Occupancy, furniture and equipment increased $166,000 due to an increase in real estate taxes and office equipment maintenance.

● Advertising and marketing expense increased $120,000 due to a 2026 brand awareness campaign.

● Professional fees increased $257,000 due to consulting and management fees related to the 2026 brand awareness campaign as well as an increase in loan-related legal fees.

● Other expenses decreased $868,000 primarily due to decreases in director deferred compensation expense stemming from market interest rate changes, a decrease in litigation expense as two nonrecurring items with limited exposure were recorded in the prior quarter, and a decrease in miscellaneous expenses as the previous quarter included an accrual related to powersport loan gap insurance refunds due to customers related to loan prepayments.

● Efficiency ratio for the quarter was 52.34% compared to 51.72% and the adjusted efficiency ratio1 was 52.06% compared to 50.80%.

Loans decreased $7.8 million driven primarily by decreases in commercial and commercial real estate – investor.

● Total loans were $5.24 billion.

● Average loans (including loans held-for-sale) for the third quarter of 2026 totaled $5.23 billion, reflecting an increase of $4.0 million.

Credit Quality key performance metrics improved significantly during the quarter, although charge-offs were higher than expected and were concentrated in a single commercial relationship.

● Nonperforming loans totaled $39.6 million compared to $56.5 million. The $16.8 million decrease reflects a $17.2 million decline in nonaccrual loans partially offset by a slight increase to loans past due 90 days or more accruing. Nonaccrual changes include $9.1 million of net principal paydowns, $6.2 million of full charge-offs, and $3.3 million of partial charge-offs, partially offset by $1.4 million of additions to nonaccrual.

● Nonperforming loans to total loans was 0.76% compared to 1.08%.

● Classified loans totaled $74.2 million compared to $132.1 million.

● Criticized loans (special mention, substandard and doubtful) to total loans was 1.88% compared to 3.05%. The quarter-over-quarter decrease is driven by a decrease of $3.4 million in special mention loans, a decrease of $17.2 million of nonaccrual loans, and a decrease of $40.7 million in substandard accruing.

● Provision for credit losses of $6.8 million was driven by $3.1 million of net charge-offs related to powersport loans, and non-powersport charge-offs were primarily isolated to two commercial loans on a single relationship.

1 Non-GAAP financial measure that management believes is useful in evaluating the financial results of the Company – refer to the non-GAAP reconciliation contained in this release.

Deposits experienced declines in noninterest bearing as well as declines in time deposits as higher-rate brokered deposits and other exception-priced time deposits assumed from Bancorp Financial, Inc. rolled off.

● Total deposits were $5.33 billion, a decrease of $117.1 million, or 2.15%.

● Cost of deposits increased two basis points to 1.02% as the cost of NOW, money market, and savings accounts all reflected increases, which were partially offset by a five basis point decline in the cost of time deposits.

● Average interest-bearing deposits decreased $55.5 million and average noninterest bearing deposits decreased $22.6 million.

Capital decreased due to share repurchases and an increase in accumulated other comprehensive unrealized loss on available-for-sale securities, partially offset by strong net income.

● Stockholders’ equity decreased $24.3 million primarily due to $3.6 million of dividends declared, an $11.5 million increase in the unrealized losses on securities and swaps due to market interest rate increases, and a $39.2 million increase in treasury stock from share repurchases, net of stock award vestings, partially offset by net income of $28.9 million.

● Share repurchases of 1,533,104 shares at an average price paid per share of $25.76 during the third quarter, for a total reduction to capital of $39.5 million, including excise taxes.

● ROATCE1 was 15.77% compared to 15.58%.

● Tangible common equity to tangible assets1 was 11.00% compared to 11.19%.

1 Non-GAAP financial measure that management believes is useful in evaluating the financial results of the Company – refer to the non-GAAP reconciliation contained in this release.

Cautionary Note Regarding Forward-Looking Statements

This earnings release and statements by our management may contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as “should,” “anticipate,” “expect,” “estimate,” “intend,” “believe,” “may,” “likely,” “will,” “forecast,” “project,” “looking forward,” “optimistic,” “hopeful,” “potential,” “progress,” “prospect,” “remain,” “deliver,” “continue,” “trend,” “momentum,” “remainder,” “beyond,” “build,” and “near” or other statements that indicate future events or expectations. Examples of forward-looking statements include, but are not limited to, statements regarding the economic outlook, balance sheet growth, building capital, credit quality trends, the adequacy of our allowance for credit losses, and future share repurchases. Such forward-looking statements are subject to risks, uncertainties, and other factors, which could cause actual results to differ materially from future results expressed or implied by such forward-looking statements. The following factors, among others, could cause actual results to differ materially from the anticipated results or other expectations expressed in the forward-looking statements:

● the strength of the United States economy in general and the strength of the local economies in which we conduct our operations may be different than expected;

● the rate of delinquencies and amounts of charge-offs, the level of the allowance for credit losses, the rates of loan growth, or adverse changes in asset quality in our loan portfolio, which may result in increased credit risk-related losses and expenses;

● adverse developments in the commercial real estate market, including increased vacancy rates, declining property values, or borrower distress, particularly in the office sector, which could result in increased credit losses or require additional provisions;

● changes in legislation, regulation, policies, or administrative practices, whether by judicial, governmental, or legislative action;

● risks related to pending or future acquisitions, if any, including execution and integration risks;

● adverse conditions in the stock market, the public debt market and other capital markets (including changes in interest rate conditions) could have a negative impact on us;

● changes in interest rates, which have affected and may continue to affect our deposit and funding costs, net income, prepayment penalty income, mortgage banking income, and other future cash flows, or the market value of our assets, including our investment securities;

● elevated inflation which causes adverse risk to the overall economy, and could indirectly pose challenges to our clients and to our business; and

● the adverse effects of events beyond our control that may have a destabilizing effect on financial markets and the economy, such as trade disputes, epidemics and pandemics, war or terrorist activities, essential utility outages, deterioration in the global economy, instability in the credit markets, disruptions in our customers’ supply chains or disruptions in transportation, and disruptions caused by widespread cybersecurity incidents.

Additional risks and uncertainties are contained in the “Risk Factors” and forward-looking statements disclosures in our most recent Annual Report on Form 10-K, and Quarterly Reports on Form 10-Q. The inclusion of this forward-looking information should not be construed as a representation by us or any person that future events, plans, or expectations contemplated by us will be achieved. We undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise, except as required by law.

Conference Call

We will host a call on Thursday, October 22, 2026, at 10:00 a.m. Eastern Time (9:00 a.m. Central Time) to discuss our third quarter 2026 financial results. Investors may listen to our earnings call via a live webcast by accessing the link provided below, or alternatively, on the Events section of the Old Second Investor Relations website (https://investors.oldsecond.com/events). Investors are encouraged to register at the webcast link at least 10 minutes prior to the scheduled start of the call.

Webcast URL: https://www.webcaster5.com/Webcast/Page/2239/54568

A replay of the webcast will be available under the Events section of the Old Second Investor Relations website (https://investors.oldsecond.com/events) for up to one year after the earnings call date.

Non-GAAP Presentations

We consider the use of select non-GAAP financial measures and ratios to be useful for financial and operational decision-making and useful in evaluating period-to-period comparisons. We believe that these non-GAAP financial measures provide meaningful supplemental information regarding our performance by excluding certain expenditures or assets or by adjusting certain items that we believe are not indicative of our primary business operating results or by presenting certain metrics on a fully tax-equivalent basis. We believe these measures provide investors with information regarding balance sheet profitability, and we believe that management and investors benefit from referring to these non-GAAP financial measures in assessing our performance and when planning, forecasting, analyzing, and comparing past, present and future periods.

These non-GAAP financial measures should not be considered as a substitute for GAAP financial measures, and we strongly encourage investors to review the GAAP financial measures included in this earnings release and not to place undue reliance upon any single financial measure. In addition, because non-GAAP financial measures are not standardized, it may not be possible to compare the non-GAAP financial measures presented in this earnings release with other companies’ non-GAAP financial measures having the same or similar names. The tables beginning on page 13 provide a reconciliation of each non-GAAP financial measure to the most comparable GAAP equivalent.

Management has disclosed in this earnings release certain non-GAAP financial measures to evaluate and measure our performance, including the presentation of adjusted net income, adjusted diluted earnings per share, adjusted return on average assets, net interest income and net interest margin on a fully tax-equivalent basis, our adjusted efficiency ratio, tangible common equity to tangible assets, and return on average tangible common equity, including on an adjusted basis. The net interest margin on a fully tax-equivalent basis is calculated by dividing net interest income on a tax equivalent basis by average earning assets for the period. The tangible measures exclude goodwill and other intangible assets, and management believes they are useful in evaluating our capital adequacy and the return generated on our tangible capital base. Consistent with industry practice, management has disclosed the efficiency ratio including and excluding certain items, which is discussed in the efficiency ratio presentation on page 14.

Financial Highlights

Quarters Ended

(Dollars in thousands - unaudited)

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Balance sheet summary

Total assets

6,778,591

6,870,305

6,849,221

6,902,675

6,991,754

Total securities available-for-sale

978,576

1,040,760

1,115,443

1,090,523

1,157,480

Total loans

5,238,057

5,245,870

5,185,237

5,252,131

5,264,505

Total deposits

5,327,564

5,444,688

5,564,999

5,596,069

5,760,250

Total liabilities

5,900,039

5,967,494

5,955,924

6,005,907

6,125,069

Total equity

878,552

902,811

893,297

896,768

866,685

Total tangible assets

6,629,195

6,719,760

6,697,509

6,749,787

6,836,565

Total tangible equity

729,156

752,266

741,585

743,880

711,496

Income statement summary

Net interest income

84,049

83,329

81,144

83,051

82,775

Provision for credit losses

6,750

7,500

9,500

3,000

19,653

Noninterest income

13,070

13,261

12,630

12,154

13,109

Noninterest expense

51,622

51,252

50,210

52,935

63,163

Net income

28,940

28,179

25,585

28,787

9,871

Effective tax rate

25.31

25.53

24.89

26.69

24.46

Profitability ratios

Return on average assets (ROAA)

1.69

1.65

1.51

1.64

0.56

Return on average equity (ROAE)

12.76

12.57

11.43

12.92

4.61

Net interest margin (tax-equivalent) 1

5.27

5.23

5.14

5.09

5.05

Efficiency ratio

52.34

51.72

52.40

53.98

64.46

Return on average tangible common equity (ROATCE) 1

15.77

15.58

14.20

16.15

6.16

Tangible common equity to tangible assets (TCE/TA) 1

11.00

11.19

11.07

11.02

10.41

Per share data

Diluted earnings per share

0.56

0.54

0.48

0.54

0.18

Tangible book value per share

14.75

14.77

14.35

14.12

13.51

Company capital ratios 2

Common equity tier 1 capital ratio

13.13

13.28

13.13

12.99

12.44

Tier 1 risk-based capital ratio

13.56

13.70

13.55

13.41

12.85

Total risk-based capital ratio

15.05

15.26

15.64

15.46

15.10

Tier 1 leverage ratio

11.99

12.05

11.88

11.70

11.21

Bank capital ratios 2, 3

Common equity tier 1 capital ratio

13.65

13.72

13.80

13.17

13.14

Tier 1 risk-based capital ratio

13.65

13.72

13.80

13.17

13.14

Total risk-based capital ratio

14.63

14.77

14.88

14.22

14.39

Tier 1 leverage ratio

12.05

12.09

11.49

11.45

1 See the discussion entitled “Non-GAAP Presentations” above and the tables on pages 13 and 15 that provide a reconciliation of this non-GAAP financial measure to the most comparable GAAP equivalent.

2 Both the Company and the Bank ratios are inclusive of a capital conservation buffer of 2.50%, and both are subject to the minimum capital adequacy guidelines of 7.00%, 8.50%, 10.50%, and 4.00% for the Common equity tier 1, Tier 1 risk-based, Total risk-based and Tier 1 leverage ratios, respectively.

3 The prompt corrective action provisions are applicable only at the Bank level, and are 6.50%, 8.00%, 10.00%, and 5.00% for the Common equity tier 1, Tier 1 risk-based, Total risk-based and Tier 1 leverage ratios, respectively.

Old Second Bancorp, Inc. and Subsidiaries

Consolidated Balance Sheets

(In thousands - unaudited)

Quarters Ended

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Assets

Cash and due from banks

42,155

47,964

48,100

51,665

53,099

Interest earning deposits with financial institutions

65,948

95,369

67,627

72,360

63,426

Cash and cash equivalents

108,103

143,333

115,727

124,025

116,525

Securities available-for-sale, at fair value

978,576

1,040,760

1,115,443

1,090,523

1,157,480

Federal Home Loan Bank Chicago (“FHLBC”) and Federal Reserve Bank Chicago (“FRBC”) stock

40,811

40,125

31,350

32,025

28,282

Loans held-for-sale

1,407

2,349

4,344

3,645

1,463

Loans

5,238,057

5,245,870

5,185,237

5,252,131

5,264,505

Less: allowance for credit losses on loans

64,189

70,380

72,126

72,301

75,037

Net loans

5,173,868

5,175,490

5,113,111

5,179,830

5,189,468

Premises and equipment, net

83,364

84,505

85,634

86,645

87,714

Other real estate owned, net

622

632

1,427

6,416

Mortgage servicing rights, at fair value

10,690

9,825

9,579

9,459

9,549

Goodwill

129,196

130,262

Core deposit intangible ("CDI")

20,200

21,349

22,516

23,692

24,927

Bank-owned life insurance (“BOLI”)

134,288

133,493

131,563

130,481

129,057

Deferred tax assets, net

33,260

28,689

31,321

31,276

33,374

Other assets

64,828

60,569

58,805

60,451

77,237

Total assets

6,778,591

6,870,305

6,849,221

6,902,675

6,991,754

Liabilities

Deposits:

Noninterest bearing demand

1,671,745

1,746,755

1,755,548

1,739,117

1,738,028

Interest bearing:

Savings, NOW, and money market

2,772,737

2,771,532

2,795,038

2,745,540

2,763,990

Time

883,082

926,401

1,014,413

1,111,412

1,258,232

Total deposits

5,327,564

5,444,688

5,564,999

5,596,069

5,760,250

Securities sold under repurchase agreements

29,908

23,241

23,130

23,769

24,290

Other short-term borrowings

395,000

375,000

200,000

215,000

165,000

Junior subordinated debentures

25,774

Subordinated debentures

29,808

29,798

59,574

59,552

59,531

Notes payable and other borrowings

9,893

14,850

14,837

14,825

14,812

Other liabilities

82,092

54,143

67,610

70,918

75,412

Total liabilities

5,900,039

5,967,494

5,955,924

6,005,907

6,125,069

Stockholders’ Equity

Common stock

53,015

Additional paid-in capital

340,751

339,616

338,418

341,451

340,108

Retained earnings

609,074

583,701

559,129

537,231

512,131

Accumulated other comprehensive loss, net

(43,395)

(31,861)

(31,095)

(28,738)

(32,294)

Treasury stock

(80,893)

(41,660)

(26,170)

(6,191)

(6,275)

Total stockholders’ equity

878,552

902,811

893,297

896,768

866,685

Total liabilities and stockholders’ equity

6,778,591

6,870,305

6,849,221

6,902,675

6,991,754

Old Second Bancorp, Inc. and Subsidiaries

Consolidated Statements of Income

(In thousands, except share data - unaudited)

Three Months Ended

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Interest and dividend income

Loans, including fees

91,356

89,845

87,138

90,925

91,301

Loans held-for-sale

Securities:

Taxable

8,416

9,088

8,949

9,136

9,872

Tax exempt

1,079

1,132

1,155

1,219

1,235

Dividends from FHLBC and FRBC stock

672

535

512

390

381

Interest earning deposits with financial institutions

537

527

549

598

1,255

Total interest and dividend income

102,091

101,189

98,346

102,303

104,075

Interest expense

Savings, NOW, and money market deposits

8,105

7,512

7,147

7,906

9,043

Time deposits

5,757

6,199

7,217

8,665

10,896

Securities sold under repurchase agreements

Other short-term borrowings

3,145

2,989

1,791

1,644

308

Junior subordinated debentures

269

289

296

288

Subordinated debentures

542

675

546

547

Notes payable and other borrowings

180

156

155

158

Total interest expense

18,042

17,860

17,202

19,252

21,300

Net interest and dividend income

84,049

83,329

81,144

83,051

82,775

Provision for credit losses

6,750

7,500

9,500

3,000

19,653

Net interest and dividend income after provision for credit losses

77,299

75,829

71,644

80,051

63,122

Noninterest income 1

Wealth management

3,682

3,628

3,383

3,537

3,515

Service charges on deposits

3,134

3,075

3,130

3,125

3,202

Secondary mortgage fees

101

166

121

123

Mortgage servicing rights mark to market gain (loss)

623

(152)

(428)

(389)

Mortgage servicing income

467

464

497

444

469

Net gain on sales of mortgage loans

363

640

555

657

620

Securities gains (losses), net

(1)

Change in cash surrender value of BOLI

796

1,469

1,082

834

1,175

Death benefit realized on BOLI

430

Card related income

2,479

2,483

2,350

2,548

2,581

Other income

1,426

1,488

1,664

1,306

1,415

Total noninterest income

13,070

13,261

12,630

12,154

13,109

Noninterest expense 1

Salaries and employee benefits

30,846

30,103

29,673

30,996

39,723

Occupancy, furniture and equipment

5,284

5,118

5,371

5,092

4,937

Computer and data processing

3,258

3,217

3,375

4,798

4,002

FDIC insurance

746

759

720

854

Net teller & bill paying

754

724

716

701

691

General bank insurance

355

351

353

354

437

Amortization of core deposit intangible

1,149

1,167

1,176

1,235

1,251

Advertising and marketing expense

603

483

551

437

650

Card related expense

1,589

1,604

1,519

1,652

1,708

Professional fees

1,417

1,160

1,299

1,265

3,145

Consumer credit expense

1,725

1,720

1,522

1,451

1,368

Other real estate expense, net

(30)

(186)

128

Other expense

3,926

4,794

4,082

4,153

4,269

Total noninterest expense

51,622

51,252

50,210

52,935

63,163

Income before income taxes

38,747

37,838

34,064

39,270

13,068

Provision for income taxes

9,807

9,659

8,479

10,483

3,197

Net income

28,940

28,179

25,585

28,787

9,871

Basic earnings per share

0.57

0.55

0.49

0.55

0.19

Diluted earnings per share

0.56

0.54

0.48

0.54

0.18

Dividends declared per share

0.07

0.06

Ending common shares outstanding

49,417,867

50,938,962

51,665,660

52,669,224

52,664,535

Weighted-average basic shares outstanding

50,302,629

51,250,245

52,450,306

52,667,899

52,686,391

Weighted-average diluted shares outstanding

51,145,790

52,120,337

53,303,072

53,480,431

53,509,690

1 Certain items in prior periods have been reclassified to conform to the current presentation.

Analysis of Average Balances,

Tax Equivalent Income / Expense and Rates

(Dollars in thousands - unaudited)

Quarters Ended

September 30, 2026

June 30, 2026

September 30, 2025

Average

Income /

Rate

Average

Income /

Rate

Average

Income /

Rate

Balance

Expense

Balance

Expense

Balance

Expense

Assets

Interest earning deposits with financial institutions

65,381

537

3.26

64,839

527

3.26

119,619

1,255

4.16

Securities:

Taxable

891,503

8,416

3.75

955,176

9,088

3.82

1,016,279

9,872

3.85

Non-taxable (TE)1

129,636

1,366

4.18

140,876

1,433

4.08

149,621

1,563

4.14

Total securities (TE)1

1,021,139

9,782

3.80

1,096,052

10,521

3.85

1,165,900

11,435

3.89

FHLBC and FRBC Stock

38,576

672

6.91

36,676

535

5.85

25,961

381

5.82

Loans and loans held-for-sale1, 2

5,227,120

91,400

6.94

5,223,093

89,921

6.91

5,217,349

91,342

6.95

Total interest earning assets

6,352,216

102,391

6.40

6,420,660

101,504

6.34

6,528,829

104,413

6.34

Cash and due from banks

45,146

46,700

51,357

Allowance for credit losses on loans

(70,983)

(72,418)

(72,354)

Other noninterest earning assets

460,566

457,995

491,421

Total assets

6,786,945

6,852,937

6,999,253

Liabilities and Stockholders' Equity

NOW accounts

721,922

1,102

0.61

717,468

897

0.50

668,439

825

0.49

Money market accounts

961,994

4,704

1.94

948,319

4,400

1.86

954,964

4,979

2.07

Savings accounts

1,098,934

2,299

0.83

1,109,381

2,215

0.80

1,175,011

3,239

1.09

Time deposits

905,298

5,757

2.52

968,464

6,199

2.57

1,347,455

10,896

3.21

Interest bearing deposits

3,688,148

13,862

1.49

3,743,632

13,711

1.47

4,145,869

19,939

1.91

Securities sold under repurchase agreements

24,059

0.73

21,337

0.75

33,382

0.71

Other short-term borrowings

321,413

3,145

3.88

312,803

2,989

3.83

25,978

308

4.70

Junior subordinated debentures

25,774

269

4.14

25,774

289

4.50

25,774

288

4.43

Subordinated debentures

29,803

542

7.22

34,373

675

7.88

59,521

547

3.65

Notes payable and other borrowings

13,938

180

5.12

14,844

156

4.22

14,806

158

4.23

Total interest bearing liabilities

4,103,135

18,042

1.74

4,152,763

17,860

1.73

4,305,330

21,300

1.96

Noninterest bearing deposits

1,722,851

1,745,475

1,782,193

Other liabilities

61,430

55,582

61,732

Stockholders' equity

899,529

899,117

849,998

Total liabilities and stockholders' equity

6,786,945

6,852,937

6,999,253

Net interest income (GAAP)

84,049

83,329

82,775

Net interest margin (GAAP)

5.25

5.21

5.03

Net interest income (TE)1

84,349

83,644

83,113

Net interest margin (TE)1

5.27

5.23

5.05

Interest bearing liabilities to earning assets

64.59

64.68

65.94

1 Tax equivalent (TE) basis is calculated using a marginal tax rate of 21% in 2026 and 2025. See the discussion entitled “Non-GAAP Presentations” above and the tables beginning on page 13 that provide a reconciliation of each non-GAAP measure to the most comparable GAAP equivalent.

2 Interest income from loans is shown on a TE basis, which is a non-GAAP financial measure as discussed in the table on page 13, and includes loan fee income of $1.8 million for the third quarter of 2026, loan fee income of $2.0 million for the second quarter of 2026, and loan fee income of $1.2 million for the third quarter of 2025. Nonaccrual loans are included in the above stated average balances.

Loans and Credit Quality

Loans

Quarters Ended

(Dollars in thousands)

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Commercial

867,362

913,527

845,278

842,130

786,095

Leases

554,370

537,197

539,116

548,256

550,201

Commercial real estate – investor

1,131,857

1,159,168

1,169,318

1,212,384

1,257,328

Commercial real estate – owner occupied

684,169

667,645

702,986

706,567

680,412

Construction

153,491

153,553

143,563

173,630

176,387

Residential real estate – investor

65,679

65,133

69,763

70,225

69,362

Residential real estate – owner occupied

247,515

242,768

239,711

230,432

231,547

Multifamily

370,431

363,352

357,131

339,131

378,213

HELOC

245,938

239,307

235,637

235,293

234,885

Powersport

689,229

683,939

674,116

696,959

715,498

Other1

228,016

220,281

208,618

197,124

184,577

Total loans

5,238,057

5,245,870

5,185,237

5,252,131

5,264,505

1 The “Other” classification includes consumer loans, such as collector cars, manufactured homes, and solar loans, as well as overdrafts.

Nonperforming assets

Quarters Ended

(Dollars in thousands)

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Nonaccrual loans

36,579

53,747

62,636

47,952

34,126

Loans past due 90 days or more and still accruing interest

3,057

2,736

12,868

4,879

13,859

Total nonperforming loans

39,636

56,483

75,504

52,831

47,985

Other real estate owned

622

632

1,427

6,416

Repossessed assets 1

1,279

819

858

1,363

2,088

Total nonperforming assets

40,915

57,924

76,994

55,621

56,489

30-89 days past due loans and still accruing interest

43,553

22,499

50,036

52,169

22,415

Nonaccrual loans to total loans

0.70

1.02

1.21

0.91

0.65

Nonperforming loans to total loans

0.76

1.08

1.46

1.01

0.91

Nonperforming assets to total loans plus OREO and repossessed assets

0.78

1.10

1.48

1.06

1.07

Purchased credit-deteriorated loans to total loans

1.00

1.19

1.35

1.50

1.61

Allowance for credit losses

64,189

70,380

72,126

72,301

75,037

Allowance for credit losses to total loans

1.23

1.34

1.39

1.38

1.43

Allowance for credit losses to nonaccrual loans

175.48

130.95

115.15

150.78

219.88

1 Repossessed assets are reported in other assets.

The following table shows classified loans by segment, which include nonaccrual loans, purchased credit deteriorated (“PCD”) loans if the risk rating so indicates, and all other loans considered substandard, for the following periods.

Classified loans

Quarters Ended

(Dollars in thousands)

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Commercial

13,190

39,646

50,640

51,587

50,680

Leases

1,729

2,930

2,604

2,428

1,277

Commercial real estate – investor

12,730

11,262

14,959

14,245

2,853

Commercial real estate – owner occupied

26,546

58,582

60,594

64,081

72,020

Construction

12,866

12,976

12,983

11,421

1,612

Residential real estate – investor

1,030

662

1,012

1,142

1,228

Residential real estate – owner occupied

2,249

2,076

1,886

1,897

1,839

Multifamily

1,254

1,197

1,489

1,494

1,183

HELOC

2,355

2,250

1,832

1,466

1,538

Powersport

145

198

204

Other1

154

318

369

270

Total classified loans

74,248

132,097

148,572

150,099

134,260

1 The “Other” classification includes consumer loans, such as collector cars, manufactured homes, and solar loans, as well as overdrafts.

Loan charge-offs, net of recoveries

Quarters Ended

(Dollars in thousands)

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Commercial

9,171

2,983

1,298

(44)

385

Leases

172

344

197

848

Commercial real estate – investor

(14)

2,804

3,919

(14)

(15)

Commercial real estate – owner occupied

(1)

(5)

1,125

(2)

Construction

(46)

Residential real estate – investor

(3)

(1)

(2)

(1)

(2)

Residential real estate – owner occupied

(10)

(21)

(7)

(11)

(7)

Multifamily

181

HELOC

(10)

(14)

(6)

(49)

(19)

Powersport

3,133

2,826

3,894

4,466

2,980

Other 1

288

328

488

494

805

Net charge-offs (recoveries)

12,726

9,248

9,776

5,981

5,108

1 The “Other” classification includes consumer loans, such as collector cars, manufactured homes, and solar loans, as well as overdrafts.

Old Second Bancorp, Inc. and Subsidiaries

Quarterly Consolidated Average Balance

(In thousands - unaudited)

Quarters Ended

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Assets

Cash and due from banks

45,146

46,700

48,252

52,040

51,357

Interest earning deposits with financial institutions

65,381

64,839

67,571

66,430

119,619

Cash and cash equivalents

110,527

111,539

115,823

118,470

170,976

Securities available-for-sale, at fair value

1,021,139

1,096,052

1,115,493

1,129,633

1,165,900

Federal Home Loan Bank Chicago (“FHLBC”) and Federal Reserve Bank Chicago (“FRBC”) stock

38,576

36,676

31,540

30,085

25,961

Loans held-for-sale

1,815

3,280

2,023

3,254

1,975

Loans

5,225,305

5,219,813

5,205,721

5,275,389

5,215,374

Less: allowance for credit losses on loans

70,983

72,418

71,869

73,718

72,354

Net loans

5,154,322

5,147,395

5,133,852

5,201,671

5,143,020

Premises and equipment, net

84,252

85,395

86,260

87,449

88,304

Other real estate owned, net

616

626

853

4,410

6,464

Mortgage servicing rights, at fair value

9,899

9,693

9,383

9,490

9,632

Goodwill

129,196

130,135

127,873

Core deposit intangible ("CDI")

20,758

21,916

23,073

24,281

25,539

Bank-owned life insurance (“BOLI”)

133,768

132,046

130,930

130,151

128,870

Deferred tax assets, net

29,477

31,296

30,342

32,705

30,375

Other assets

52,600

47,827

50,396

58,443

74,364

Total assets

6,786,945

6,852,937

6,859,164

6,960,177

6,999,253

Liabilities

Deposits:

Noninterest bearing demand

1,722,851

1,745,475

1,738,504

1,781,374

1,782,193

Interest bearing:

Savings, NOW, and money market

2,782,850

2,775,168

2,762,746

2,764,609

2,798,414

Time

905,298

968,464

1,062,623

1,179,966

1,347,455

Total deposits

5,410,999

5,489,107

5,563,873

5,725,949

5,928,062

Securities sold under repurchase agreements

24,059

21,337

24,795

23,464

33,382

Other short-term borrowings

321,413

312,803

189,056

159,565

25,978

Junior subordinated debentures

25,774

Subordinated debentures

29,803

34,373

59,564

59,542

59,521

Notes payable and other borrowings

13,938

14,844

14,831

14,819

14,806

Other liabilities

61,430

55,582

73,284

67,078

61,732

Total liabilities

5,887,416

5,953,820

5,951,177

6,076,191

6,149,255

Stockholders’ Equity

Common stock

53,015

Additional paid-in capital

340,227

339,145

340,459

340,870

339,612

Retained earnings

598,284

573,158

551,491

526,910

500,075

Accumulated other comprehensive loss, net

(33,884)

(31,113)

(26,361)

(30,594)

(36,823)

Treasury stock

(58,113)

(35,088)

(10,617)

(6,215)

(5,881)

Total stockholders’ equity

899,529

899,117

907,987

883,986

849,998

Total liabilities and stockholders’ equity

6,786,945

6,852,937

6,859,164

6,960,177

6,999,253

Total Earning Assets

6,352,216

6,420,660

6,422,348

6,504,791

6,528,829

Total Interest Bearing Liabilities

4,103,135

4,152,763

4,139,389

4,227,739

4,305,330

Reconciliation of Non-GAAP Financial Measures

The tables below provide a reconciliation of each non-GAAP financial measure to the most comparable GAAP measure for the periods indicated. Dollar amounts below in thousands:

Net Income and Earnings Per Share - GAAP and Adjusted

Three Months Ended

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Income before income taxes (GAAP)

38,747

37,838

34,064

39,270

13,068

Pre-tax income adjustments:

Provision for credit losses - Day Two

13,153

Securities losses (gains), net

(8)

Death benefit related to BOLI

(430)

MSR (gains) losses

(623)

152

428

389

Acquisition related costs, net of gains on branch sales

526

349

2,296

11,508

Adjusted net income before taxes

38,125

38,516

34,565

41,986

37,689

Taxes on adjusted net income

9,649

9,832

8,604

11,208

9,326

Adjusted net income (non-GAAP)

28,476

28,684

25,961

30,778

28,363

Basic earnings per share (GAAP)

0.57

0.55

0.49

0.55

0.19

Diluted earnings per share (GAAP)

0.56

0.54

0.48

0.54

0.18

Adjusted basic earnings per share (non-GAAP)

0.57

0.56

0.49

0.59

0.54

Adjusted diluted earnings per share (non-GAAP)

0.55

0.49

0.58

0.53

Total average assets

6,786,945

6,852,937

6,859,164

6,960,177

6,999,253

Return on average assets (GAAP)

1.69

1.65

1.51

1.64

0.56

Adjusted return on average assets (non-GAAP)

1.66

1.68

1.53

1.75

1.61

Quarters Ended

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Net Interest Margin

Interest income (GAAP)

102,091

101,189

98,346

102,303

104,075

Taxable-equivalent adjustment:

Loans

Securities

287

301

307

324

328

Interest income (TE)

102,391

101,504

98,666

102,636

104,413

Interest expense (GAAP)

18,042

17,860

17,202

19,252

21,300

Net interest income (TE)

84,349

83,644

81,464

83,384

83,113

Net interest income (GAAP)

84,049

83,329

81,144

83,051

82,775

Average interest earning assets

6,352,216

6,420,660

6,422,348

6,504,791

6,528,829

Net interest margin (GAAP)

5.25

5.21

5.12

5.07

5.03

Net interest margin (TE)

5.27

5.23

5.14

5.09

5.05

GAAP

Three Months Ended

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Efficiency Ratio (GAAP)

Noninterest expense

51,622

51,252

50,210

52,935

63,163

Less amortization of core deposit intangibles

1,149

1,167

1,176

1,235

1,251

Less other real estate expense, net

(30)

(186)

128

Less acquisition related costs, net of gains on branch sales

N/A

Noninterest expense less adjustments

50,503

50,033

49,220

51,619

61,784

Net interest income

84,049

83,329

81,144

83,051

82,775

Taxable-equivalent adjustment:

Loans

N/A

Securities

N/A

Net interest income including adjustments

84,049

83,329

81,144

83,051

82,775

Noninterest income

13,070

13,261

12,630

12,154

13,109

Less death benefit related to BOLI

430

Less securities (losses) gains

(1)

Less MSRs mark to market gains (losses)

623

(152)

(428)

(389)

Taxable-equivalent adjustment:

Change in cash surrender value of BOLI

N/A

Noninterest income including adjustments

12,448

13,413

12,782

12,574

13,069

Net interest income including adjustments plus noninterest income including adjustments

96,497

96,742

93,926

95,625

95,844

Efficiency ratio (GAAP)

52.34

51.72

52.40

53.98

64.46

N/A - Not applicable.

Non-GAAP

Three Months Ended

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Adjusted Efficiency Ratio (non-GAAP)

Noninterest expense

51,622

51,252

50,210

52,935

63,163

Less amortization of core deposit intangibles

1,149

1,167

1,176

1,235

1,251

Less other real estate expense, net

(30)

(186)

128

Less acquisition related costs, net of gains on branch sales

526

349

2,296

11,508

Noninterest expense less adjustments

50,503

49,507

48,871

49,323

50,276

Net interest income

84,049

83,329

81,144

83,051

82,775

Taxable-equivalent adjustment:

Loans

Securities

287

301

307

324

328

Net interest income including adjustments

84,349

83,644

81,464

83,384

83,113

Noninterest income

13,070

13,261

12,630

12,154

13,109

Less death benefit related to BOLI

430

Less securities (losses) gains

(1)

Less MSRs mark to market gains (losses)

623

(152)

(428)

(389)

Taxable-equivalent adjustment:

Change in cash surrender value of BOLI

212

390

288

222

312

Noninterest income including adjustments

12,660

13,803

13,070

12,796

13,381

Net interest income including adjustments plus noninterest income including adjustments

97,009

97,447

94,534

96,180

96,494

Adjusted efficiency ratio (non-GAAP)

52.06

50.80

51.70

51.28

52.10

Quarters Ended

September 30,

June 30,

March 31,

December 31,

September 30,

2026

2025

Adjusted Return on Average Tangible Common Equity Ratio

Net income (GAAP)

28,940

28,179

25,585

28,787

9,871

Income before income taxes (GAAP)

38,747

37,838

34,064

39,270

13,068

Pre-tax income adjustments:

Provision for credit losses - Day Two

13,153

Securities losses (gains), net

(8)

MSR (gains) losses

(623)

152

428

389

Acquisition related costs, net of gains on branch sales

526

349

2,296

11,508

Death benefit realized on BOLI

(430)

Amortization of core deposit intangibles

1,149

1,167

1,176

1,235

1,251

Adjusted net income, excluding intangibles amortization, before taxes

39,274

39,683

35,741

43,221

38,940

Taxes on adjusted net income

9,940

10,130

8,896

11,538

9,632

Adjusted net income (non-GAAP)

29,334

29,553

26,845

31,683

29,308

Total Average Common Equity

899,529

899,117

907,987

883,986

849,998

Less average goodwill and intangible assets

149,954

151,112

152,269

154,416

153,412

Average tangible common equity (non-GAAP)

749,575

748,005

755,718

729,570

696,586

Total Common Equity

878,552

902,811

893,297

896,768

866,685

Less goodwill and intangible assets

149,396

150,545

151,712

152,888

155,189

Tangible common equity

729,156

752,266

741,585

743,880

711,496

Total Assets

6,778,591

6,870,305

6,849,221

6,902,675

6,991,754

Less goodwill and intangible assets

149,396

150,545

151,712

152,888

155,189

Tangible assets

6,629,195

6,719,760

6,697,509

6,749,787

6,836,565

Return on average common equity (GAAP)

12.76

12.57

11.43

12.92

4.61

Return on average tangible common equity (non-GAAP)

15.77

15.58

14.20

16.15

6.16

Adjusted return on average tangible common equity (non-GAAP)

15.53

15.85

14.41

17.23

16.69

Tangible common equity to tangible assets

11.00

11.19

11.07

11.02

10.41

EX-99.2

Filename: osbc-ex99d2.htm · Sequence: 3

Loan Portfolio Disclosures

AS OF SEPTEMBER 30, 2026

Exhibit 99.2

Portfolio Segment Outstanding Classified Allowance

Commercial (incl. Leases) $1,422 $15 1.05%

Commercial Real Estate Investor $1,132 $13 1.64%

Commercial Real Estate Owner Occ. $684 $27 0.40%

Construction $154 $13 0.73%

Residential Real Estate $313 $3 0.81%

Multifamily $370 $1 0.41%

HELOC $246 $2 1.37%

Powersport $689 - 2.70%

Other (less than $100 million) $228 - 2.01%

Total $5,238 $74 1.23%

Construction

Commercial RE

Investor

22%

Commercial RE

Owner Occ.

13%

Commercial

(inc. Leases)

27%

Multifamily

Residential

Real Estate

HELOC

Other (less than

$100 million)

Powersport

13%

Loan Portfolio Composition (in millions)

Q3 2026 Loan Portfolio Disclosures

Total Loans and Allowance for Credit Losses Trend (in millions)

$3,940 $3,999 $5,265 $5,252 $5,185 $5,246 $5,238

$42 $43

$75 $72 $72 $70

$64

$10

$20

$30

$40

$50

$60

$70

$80

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

3/31/2025 6/30/2025 9/30/2025 12/31/2025 3/31/2026 6/30/2026 9/30/2026

Total Loans ACL

Criticized Loans (in millions)

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

$50

$100

$150

$200

$250

$300

$350

3/31/23 6/30/23 9/30/23 12/31/23 3/31/24 6/30/24 9/30/24 12/31/24 3/31/25 6/30/25 9/30/25 12/31/25 3/31/26 6/30/26 9/30/26

Office CRE Healthcare Other Criticized Loans/ Total Loans

Q3 2026 Loan Portfolio Disclosures

$4,988

$632 $622

$1,498

$6,416

$1,427

$234 $2,088

$1,363

$858 $819 $1,279

$2,000

$4,000

$6,000

$8,000

$10,000

6/30/25 9/30/25 12/31/25 3/31/26 6/30/26 9/30/26

OREO OREO Under Contract Repossessed Assets

OREO and Repossessed Assets (in thousands)

Participation / Syndication Portfolio Mix (in millions)

Participation / Syndication Portfolio Exposure (in millions)

Parti / Syndi Portfolio Outstanding SNC Classified

Manufacturing C&I $39 - -

Multifamily $36 - -

Retail CRE $26 - -

Healthcare $24 - -

Office CRE $17 - -

Hotel CRE $15 - -

Administration C&I $15 - -

Construction C&I $15 - -

Other (under $10 million) $26 $7 -

Total Purchased $213 $7 -

Manufacturing

C&I

Multifamily 18%

17%

Retail CRE

12%

Healthcare

11%

Office CRE

8% Other

34%

$543 $463 $362 $285 $213

14.2%

11.1%

8.9%

4.5% 4.1%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

$100

$200

$300

$400

$500

$600

12/31/2022 12/31/2023 12/31/2024 12/31/2025 9/30/2026

Outstanding % of Total Commitments

Q3 2026 Loan Portfolio Disclosures

Property Type Outstanding LTV Classified Allowance

Retail $341 54% $2 1.01%

Industrial $243 49% - 1.06%

Office $152 68% - 2.22%

Senior Living $109 58% - 1.11%

Parking Garage $76 49% - 0.85%

Hotel $67 61% - 1.52%

Other (under $50 million) $144 68% $11 4.51%

Total $1,132 57% $13 1.64%

Commercial Real Estate Investor Portfolio Composition (in millions)

Retail

30%

Office

13%

Industrial

21%

Parking Garage

Hotel

Senior Living

10%

Other (under

$50 million)

13%

Illinois

55%

Wisconsin

Texas

North Carolina

Georgia

Tennessee

Oklahoma

3% Other (under

$30 million)

19%

State Outstanding LTV Classified

Illinois $622 60% $11

Texas $82 55% -

Wisconsin $66 61% -

North Carolina $49 49% -

Oklahoma $34 61% -

Georgia $32 57% -

Tennessee $31 51% $2

Other (under $30 million) $216 49% -

Total $1,132 57% $13

Q3 2026 Loan Portfolio Disclosures

Location Outstanding LTV Classified Allowance

Illinois $124 70% - 2.49%

Chicago $22 74% - 2.42%

Suburban $102 69% - 2.40%

Oklahoma $15 64% - 0.84%

Colorado $6 51% - 0.84%

Oregon $4 73% - 0.84%

Georgia $2 59% - 0.84%

Wisconsin $1 63% - 0.84%

Total $152 68% - 2.22%

Office Commercial Real Estate Investor Portfolio Composition (in millions)

Illinois - Chicago

14%

Illinois - Suburban

67%

Oklahoma

10%

Other (less than

$5 million)

Colorado

Office Commercial Real Estate Investor Risk Profile (in millions)

Q3 2026 Loan Portfolio Disclosures

$36

$66

$18

$32

$20

$40

$60

$80

< 1 year 1-3 years 3-5 years > 5 years

Maturity Outstanding LTV DSCR

< 1 year $32 81% 1.33x

1-3 years $58 80% 1.41x

3-5 years $14 57% 1.56x

> 5 years $30 54% 1.54x

Total $134 71% 1.44x

Office Commercial Real Estate by Loan Maturity Office Commercial Real Estate > $1 million

Industry Outstanding Classified Allowance

Health Care, Social Services $275 $2 0.22%

Other Services $75 $4 0.44%

Retail Trade $62 - 0.34%

Manufacturing $57 - 0.30%

Real Estate, Leasing $33 - 0.23%

Wholesale Trade $34 - 0.13%

Accommodation, Food Service $31 $7 1.64%

Arts, Entertainment $26 $2 0.37%

Other (under $20 million) $91 $12 0.76%

Total $684 $27 0.40%

Manufacturing

Accommodation,

Food Service

Retail Trade

Real Estate,

Leasing

Healthcare

40%

Other Services

11%

Wholesale Trade

Other (under $30

million)

17%

Commercial Real Estate Owner-Occupied Portfolio Composition (in millions)

Health Care, Social Outstanding Classified Allowance

Assisted Living $137 $2 0.22%

Memory Care $62 - 0.26%

Skilled Nursing $53 - 0.16%

Child Care $6 - 0.31%

Other (under $5 million) $17 - 0.19%

Total $275 $2 0.22%

Skilled

Nursing

19%

Assisted

Living

50%

Memory Care

23%

Child Care

Other (under $5 million)

Q3 2026 Loan Portfolio Disclosures

Commercial & Industrial Outstanding Classified

Manufacturing $411 -

Construction $229 $5

Administrative, Waste Service $180 -

Professional $126 -

Finance, Insurance $102 -

Transportation, Warehousing $93 -

Real Estate, Leasing $76 -

Health Care, Social Services $56 $1

Wholesale Trade $44 $3

Other (under $20 million) $105 $6

Total $1,422 $15

Commercial (including Leases) Portfolio Composition (in millions)

Construction

16%

Manufacturing

29%

Transportation,

Warehousing

Finance, Insurance

Professional

Administration,

Waste Service

13%

Real Estate,

Leasing

5% Other (under

$60 million)

14%

Commercial Revolving Line Utilization (outstanding in millions)

$653 $587 $574 $658 $717 $718 $756 $737

55%

52% 53%

55% 57% 57%

60% 58%

30%

35%

40%

45%

50%

55%

60%

65%

70%

$400

$450

$500

$550

$600

$650

$700

$750

$800

12/31/24 3/31/25 6/30/25 9/30/25 12/31/25 3/31/26 6/30/26 9/30/26

Q3 2026 Loan Portfolio Disclosures

Origination Tier Outstanding Weighted FICO Portfolio APR %

Tier 1 $366 777 7.99%

Tier 2 $130 711 10.24%

Tier 3 $80 684 12.77%

Tier 4 $39 660 14.73%

Tier 5 $74 606 17.01%

Total $689 730 10.24%

Powersport Portfolio Composition (in millions)

Tier 1

53%

Tier 2

19%

Tier 3

11%

Tier 4

Tier 5

11%

Historical Contribution Margin

Q3 2026 Loan Portfolio Disclosures

Contribution Margin (1) 2023 (EBG) 2024 (EBG) 12/31/2025 3/31/2026 6/30/2026 9/30/2026

Portfolio APR 8.13% 9.02% 9.82% 10.14% 10.20% 10.24%

Net Promo Accretion 0.41% 0.74% 1.03% 1.30% 1.33% 1.17%

Participation -0.87% -0.87% -0.91% -1.08% -1.12% -1.00%

Net Loss -1.11% -1.39% -1.76% -2.06% -1.80% -1.80%

Net Contribution Margin 6.56% 7.52% 8.19% 8.30% 8.62% 8.60%

(1) Historical contribution margin represents Evergreen Bank Group (EBG) performance through 6/30/2025. Contribution margin presented after 6/30/2025 excludes purchase

accounting adjustments.

Asset Type Outstanding % of Total Portfolio APR %

New $521 76% 9.57%

Used $168 24% 12.46%

Total $689 10.24%

Net Charge-offs (Recoveries) (in thousands)

Portfolio 12/31/2025 (Q) 3/31/2026 (Q) 6/30/2026 (Q) 9/30/2026 (Q) 9/30/2026 (TTM) NCO(R) %

Commercial (incl. Leases) ($29) $1,495 $3,327 $9,343 $14,136 0.99%

Commercial Real Estate Investor ($14) $3,919 $2,804 ($14) $6,695 0.59%

Commercial Real Estate Owner Occupied $1,125 ($5) ($1) ($1) $1,118 0.16%

Construction - - - - - 0.00%

Residential Real Estate ($12) ($9) ($22) ($13) ($56) (0.02%)

Multifamily - - - - - 0.00%

HELOC ($49) ($6) ($14) ($10) ($79) (0.03%)

Powersport $4,466 $3,894 $2,826 $3,133 $14,319 2.08%

Other $494 $488 $328 $288 $1,598 0.70%

Total $5,981 $9,776 $9,248 $12,726 $37,731 0.72%

9/30/2025 12/31/2025 3/31/2026 6/30/2026 9/30/2026

Beginning ACL Balance $42,990 $75,037 $72,301 $72,126 $70,380

Day 1 Credit Mark (PCD) $17,540 - - - -

Day 2 Credit Mark (Non-PCD) $13,153 - - - -

Plus: Provision $6,462 $3,245 $9,602 $7,502 $6,535

Less: Net Charge-off (Recovery) $5,108 $5,981 $9,776 $9,248 $12,726

Ending ACL Balance $75,037 $72,301 $72,126 $70,380 $64,189

Allowance for Credit Losses Quarterly Rollforward(2) (in thousands)

Q3 2026 Loan Portfolio Disclosures

(2) The Allowance for Credit Losses presented excludes the Allowance for Unfunded Commitments, which totaled $2.2 million as of September 30, 2026 and is reported within

other liabilities on the Statements of Condition.

GRAPHIC

Filename: osbc-20261021x8k001.jpg · Sequence: 4

Binary file (76173 bytes)

Download osbc-20261021x8k001.jpg

GRAPHIC

Filename: osbc-ex99d1001.jpg · Sequence: 5

Binary file (53621 bytes)

Download osbc-ex99d1001.jpg

GRAPHIC

Filename: osbc-ex99d2g001.jpg · Sequence: 6

Binary file (30367 bytes)

Download osbc-ex99d2g001.jpg

GRAPHIC

Filename: osbc-ex99d2g002.jpg · Sequence: 7

Binary file (109992 bytes)

Download osbc-ex99d2g002.jpg

GRAPHIC

Filename: osbc-ex99d2g003.jpg · Sequence: 8

Binary file (94895 bytes)

Download osbc-ex99d2g003.jpg

GRAPHIC

Filename: osbc-ex99d2g004.jpg · Sequence: 9

Binary file (92287 bytes)

Download osbc-ex99d2g004.jpg

GRAPHIC

Filename: osbc-ex99d2g005.jpg · Sequence: 10

Binary file (94030 bytes)

Download osbc-ex99d2g005.jpg

GRAPHIC

Filename: osbc-ex99d2g006.jpg · Sequence: 11

Binary file (96359 bytes)

Download osbc-ex99d2g006.jpg

GRAPHIC

Filename: osbc-ex99d2g007.jpg · Sequence: 12

Binary file (98127 bytes)

Download osbc-ex99d2g007.jpg

GRAPHIC

Filename: osbc-ex99d2g008.jpg · Sequence: 13

Binary file (108741 bytes)

Download osbc-ex99d2g008.jpg

GRAPHIC

Filename: osbc-ex99d2g009.jpg · Sequence: 14

Binary file (98006 bytes)

Download osbc-ex99d2g009.jpg

GRAPHIC

Filename: osbc-ex99d2g010.jpg · Sequence: 15

Binary file (114330 bytes)

Download osbc-ex99d2g010.jpg

XML — IDEA: XBRL DOCUMENT

XML

Filename: R1.htm · Sequence: 20

v3.26.3

Document and Entity Information

Oct. 21, 2026

Document and Entity Information [Abstract]

Document Type

8-K

Document Period End Date

Oct. 21, 2026

Entity Registrant Name

OLD SECOND BANCORP INC

Entity Incorporation, State or Country Code

Securities Act File Number

000-10537

Entity Tax Identification Number

36-3143493

Entity Address, Address Line One

37 South River Street

Entity Address, City or Town

Aurora

Entity Address, State or Province

Entity Address, Postal Zip Code

60507

City Area Code

630

Local Phone Number

892-0202

Written Communications

false

Soliciting Material

false

Pre-commencement Tender Offer

false

Pre-commencement Issuer Tender Offer

false

Title of 12(b) Security

Common Stock

Trading Symbol

OSBC

Security Exchange Name

NASDAQ

Entity Emerging Growth Company

false

Entity Central Index Key

0000357173

Amendment Flag

false

- Definition

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

+ References

No definition available.

+ Details

Name:

dei_AmendmentFlag

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Area code of city

+ References

No definition available.

+ Details

Name:

dei_CityAreaCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

+ References

No definition available.

+ Details

Name:

dei_DocumentPeriodEndDate

Namespace Prefix:

dei_

Data Type:

xbrli:dateItemType

Balance Type:

Period Type:

duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:

dei_DocumentType

Namespace Prefix:

dei_

Data Type:

dei:submissionTypeItemType

Balance Type:

Period Type:

duration

- Definition

Address Line 1 such as Attn, Building Name, Street Name

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine1

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the City or Town

+ References

No definition available.

+ Details

Name:

dei_EntityAddressCityOrTown

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Code for the postal or zip code

+ References

No definition available.

+ Details

Name:

dei_EntityAddressPostalZipCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the state or province.

+ References

No definition available.

+ Details

Name:

dei_EntityAddressStateOrProvince

Namespace Prefix:

dei_

Data Type:

dei:stateOrProvinceItemType

Balance Type:

Period Type:

duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityCentralIndexKey

Namespace Prefix:

dei_

Data Type:

dei:centralIndexKeyItemType

Balance Type:

Period Type:

duration

- Definition

Indicate if registrant meets the emerging growth company criteria.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityEmergingGrowthCompany

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

+ References

No definition available.

+ Details

Name:

dei_EntityFileNumber

Namespace Prefix:

dei_

Data Type:

dei:fileNumberItemType

Balance Type:

Period Type:

duration

- Definition

Two-character EDGAR code representing the state or country of incorporation.

+ References

No definition available.

+ Details

Name:

dei_EntityIncorporationStateCountryCode

Namespace Prefix:

dei_

Data Type:

dei:edgarStateCountryItemType

Balance Type:

Period Type:

duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityRegistrantName

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityTaxIdentificationNumber

Namespace Prefix:

dei_

Data Type:

dei:employerIdItemType

Balance Type:

Period Type:

duration

- Definition

Local phone number for entity.

+ References

No definition available.

+ Details

Name:

dei_LocalPhoneNumber

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

+ Details

Name:

dei_PreCommencementIssuerTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14d

-Subsection 2b

+ Details

Name:

dei_PreCommencementTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Title of a 12(b) registered security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

+ Details

Name:

dei_Security12bTitle

Namespace Prefix:

dei_

Data Type:

dei:securityTitleItemType

Balance Type:

Period Type:

duration

- Definition

Name of the Exchange on which a security is registered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection d1-1

+ Details

Name:

dei_SecurityExchangeName

Namespace Prefix:

dei_

Data Type:

dei:edgarExchangeCodeItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14a

-Subsection 12

+ Details

Name:

dei_SolicitingMaterial

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

Name:

dei_TradingSymbol

Namespace Prefix:

dei_

Data Type:

dei:tradingSymbolItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 230

-Section 425

+ Details

Name:

dei_WrittenCommunications

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- References

No definition available.

+ Details

Name:

osbc_DocumentAndEntityInformationAbstract

Namespace Prefix:

osbc_

Data Type:

xbrli:stringItemType

Balance Type:

Period Type:

duration