Form 8-K

8-K — DEEP FISSION, INC.

Accession: 0001104659-26-117389

Filed: 2026-10-20

Period: 2026-10-20

CIK: 0001918102

SIC: 4911 (ELECTRIC SERVICES)

Item: Regulation FD Disclosure

Item: Financial Statements and Exhibits

Documents

8-K — tm2627978d1_8k.htm (Primary)

EX-99.1 — EXHIBIT 99.1 (tm2627978d1_ex99-1.htm)

EX-99.2 — EXHIBIT 99.2 (tm2627978d1_ex99-2.htm)

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2026-10-20

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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 20, 2026

Deep Fission, Inc.

(Exact name of registrant as specified in its charter)

Delaware

000-56407

87-4265302

(State or other jurisdiction

of incorporation)

(Commission File Number)

(IRS Employer

Identification No.)

2001 Addison Street, Unit 300

Berkeley, California

(Address of principal executive offices)

94704

(Zip Code)

Registrant’s

telephone number, including area code: (707) 400-0778

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:

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, par value $0.0001 per share

FISN

The Nasdaq Global Market

Indicate by check mark whether the registrant is an emerging growth

company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange

Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company x

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 7.01 – Regulation FD Disclosure

Press Release

On October 20, 2026, Deep Fission, Inc. (the “Company”)

issued a press release announcing that it had entered into a Master Energy Purchase Agreement (the “Agreement”) with the Great

Plains Development Authority relating to a planned commercial nuclear power project at the Great Plains Industrial Park in Parsons, Kansas.

The Agreement is subject to regulatory approvals and other conditions to commercial operation, and electricity purchases will depend on

actual tenant demand, with no minimum purchase obligation. A copy of the press release is furnished as Exhibit 99.1 to this Current Report

on Form 8-K (this “Current Report”) and is incorporated herein by reference.

Investor Presentation

On October 20, 2026, the Company held an investor update call. A copy

of the presentation used in connection with the call is furnished as Exhibit 99.2 to this Current Report and is incorporated herein by

reference.

The information in this Item 7.01, including Exhibits 99.1 and 99.2,

is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended

(the “Exchange Act”), or incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange

Act, except as expressly provided by specific reference in such filing.

Item 9.01 Financial Statements and Exhibits

Exhibit No.

Description

99.1

Press Release dated October 20, 2026

99.2

Investor Presentation dated October 20, 2026

104

Cover Page Interactive Data File (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.

DEEP FISSION, INC.

Date: October 20, 2026

/s/ JON GORDON

Jon Gordon

General Counsel & Secretary

EX-99.1 — EXHIBIT 99.1

EX-99.1

Filename: tm2627978d1_ex99-1.htm · Sequence: 2

Exhibit 99.1

Deep Fission

Signs Binding 25-Year Master Energy Purchase Agreement for Planned Commercial Project

Agreement with

Great Plains Development Authority covers an initial phase of up to 150 MW, targeted for September 2028 and up to 2GW by 2031

Management to

host business update call today, October 20th, at 11:00 a.m. ET

PARSONS, Kan. – October 20,

2026 – Deep Fission, Inc. (Nasdaq: FISN) today announced a Master Energy Purchase Agreement with the Great Plains Development

Authority (GPDA), a quasi-municipal entity that owns the Great Plains Industrial Park in Parsons, Kansas. It converts the parties’

December 2025 letter of intent into a definitive contract for a commercial project at the site of Deep Fission’s Department of

Energy (DOE) pilot. The agreement binds Deep Fission to pursue the project and to supply power once licensed and operating, subject to

the agreement’s terms and conditions. Under the agreement GPDA will purchase electricity generated and made available by Deep Fission

to satisfy the electricity requirements of industrial park tenants, up to the contracted capacity, with no minimum purchase obligation.

The agreement also permits GPDA to assign its purchase obligations to qualifying tenants.

The initial phase is anticipated to

be 150 MW with a target date of commercial operation on September 30, 2028, and grow through later phases to a total of 2,000 MW pending

further demand growth.

“This agreement turns a shared

vision into a binding commitment,” said Liz Muller, CEO and Co-Founder of Deep Fission. “Our approach is to bring firm power

directly to where it’s needed. Great Plains has been with us since we broke ground, and we’re proud to take this next step

together as we deliver reliable, clean, 24/7 power, with our Gravity reactor.”

The Great Plains Industrial Park covers

more than 14,000 acres in Labette County on the site of a former U.S. Army ammunition plant, with existing rail access, utilities and

space for large industrial users. Deep Fission held a groundbreaking ceremony at the park in December 2025 on its pilot reactor under

the U.S. Department of Energy (DOE) Reactor Pilot Program.

“Dependable, affordable power

is what draws employers to Southeast Kansas, and it’s what the companies we’re talking to are asking for,” said Brad

Reams, Park Director, Great Plains Development Authority. “Deep Fission’s Gravity reactor is designed to provide firm, carbon-free

electricity right here at the park, and this agreement gives us a long-term energy plan to offer.”

Deep Fission's Gravity™ Nuclear

Reactor is a pressurized water reactor that runs on standard low-enriched uranium fuel. Placing it approximately one mile underground

is designed to allow the surrounding water column and rock to provide pressure control, cooling and shielding, potentially reducing the

need for much of the surface infrastructure that conventional nuclear plants require.

Deep Fission management will discuss

the Agreement on its previously announced business update call on today Tuesday, October 20, 2026, at 11:00 a.m. ET. U.S. toll free:

1-877-425-9470. International: 1-201-389-0878. A live webcast will be available in the Investor Relations section of the Company's website

at https://www.deepfission.com/investors.

About Deep Fission

Deep Fission is developing technology

that places a small modular pressurized water reactor in a borehole approximately one mile underground. The Company's Gravity™

Nuclear Reactor approach combines established pressurized water reactor technology with a novel underground deployment model designed

to simplify construction, enhance safety, and support scalable commercial deployment. Deep Fission is focused on delivering reliable,

low-carbon baseload power to meet growing electricity demand from utilities, industrial customers, and data centers. The Company is currently

advancing the development of its first reactor project in Parsons, Kansas, and was selected for the U.S. Department of Energy's Reactor

Pilot Program.

About the Great Plains Development

Authority

Great Plains Industrial Park provides

large-scale, flexible environments located directly on the Union Pacific main line designed to support advanced industry, testing, and

innovation. With significant room for expansion and a focus on next-generation infrastructure, Great Plains is emerging as a premier

destination for enterprises shaping the future of industry and technology.

Forward-Looking Statements

This press release contains forward-looking

statements within the meaning of the federal securities laws. Forward-looking statements include, but are not limited to, statements

regarding Deep Fission’s business strategy, technology development plans, potential commercial deployments, expected regulatory

activities, planned project milestones, potential commercialization, potential revenue recognition, and the timing, feasibility, scalability,

safety, and performance of the Company’s technology. These statements include the anticipated development, capacity, commercial

operation date, expansion and performance of the Kansas project, the timing and volume of electricity purchases under the GPDA agreement,

and the potential realization of revenues from that agreement. These statements are based on current expectations and assumptions and

are subject to risks and uncertainties that could cause actual results to differ materially from those expressed or implied.

Important factors that may cause actual

results to differ materially include, among others, risks related to the Company’s early stage of development; the Company’s

ability to negotiate and enter into definitive commercial agreements; technical, engineering, drilling, construction, regulatory, licensing,

financing, supply chain, and deployment risks; the Company’s ability to obtain required approvals from the NRC, DOE, and other

governmental authorities; market adoption of the Company’s technology; and the other risks described under “Risk Factors”

and “Cautionary Note Regarding Forward-Looking Statements” in Deep Fission’s filings with the Securities and Exchange

Commission. Important factors may also include the absence of minimum electricity purchase obligations under the GPDA agreement; dependence

on electricity demand from tenants at the Great Plains Industrial Park; the ability to satisfy the conditions to commercial operation,

including NRC licensing, Kansas regulatory approvals and required delivery arrangements; and the possibility that the project may be

delayed, reduced in scope or not completed.

Forward-looking statements speak only

as of the date of this press release. Deep Fission undertakes no obligation to update any forward-looking statements, except as required

by law.

Media Contact Gabriella Velez

media@deepfission.com

Investor Relations Contact Jen

Stakich, IR@deepfission.com, (858) 794-9500

Elevate IR, (720) 330-2829, IR@deepfission.com

EX-99.2 — EXHIBIT 99.2

EX-99.2

Filename: tm2627978d1_ex99-2.htm · Sequence: 3

Exhibit

99.2

DeepFission.com

October 2026

Nasdaq: FISN

Business Update

This presentation includes forward-looking statements within the meaning of federal securities laws, including the Private Securities

Litigation Reform Act of 1995. Forward-looking statements describe future expectations, plans, results or strategies and can often be

identified by the use of terminology such as "anticipate," "believe," "could," "estimate," "expect," "intend," "may," "plan," "potential,"

"project," "seek," "should," "target," "will," "would," and similar expressions, although not all forward-looking statements contain these

identifying words. These statements include statements regarding Deep Fission's technology development, regulatory activities,

commercialization plans, anticipated reactor deployments, strategic partnerships, market opportunities, future operating performance,

financing plans and growth strategy.

Forward-looking statements are based on current expectations and assumptions and involve risks and uncertainties that could cause

actual results to differ materially from those expressed or implied. Important factors include Deep Fission's ability to obtain financing,

secure regulatory approvals, develop and deploy its technology, achieve anticipated technical and economic performance, secure

customers and commercial agreements, obtain fuel and critical supplies, manage costs and timelines, and other risks described in Deep

Fission's filings with the Securities and Exchange Commission. Deep Fission's forward-looking statements are based on information

available as of the date of publication. Except as required by law, Deep Fission does not undertake any obligation to update these

statements.

This presentation is not an offer to buy or sell, or the solicitation of an offer to buy or sell, any securities of Deep Fission, Inc. or any other

person.

Forward-looking statements

Straight to

commercial power.

Key updates:

Regulatory

NSDA approved & published for transparency

Commercial Siting

Master Energy Purchase Agreement signed in Kansas

Fuel

Standard LEU contract with Urenco

Construction

Commercial drilling & non-nuclear testing underway

Customers

Multi GWe pipeline of non-binding letters of intent

Long

-term demand is

obvious. Our focus is

delivery at scale

by 2028.

Utilities, data centers, and

defense are adding load

faster than expected

growth in supply.

Deep Fission is

moving to fill the

immediate

generation gap

Signed a first binding, conditional

energy offtake agreement in

October 2026.

Total pipeline includes data

centers, industrial parks, co

developers and strategic partners,

signaling discerning buyer belief in

Deep Fission’s capability to deliver

on time and at scale.

Leveraging three

mature technologies.

Deep Borehole Drilling

Decades

-proven commercial drilling

techniques for containment one mile

underground.

Geothermal Technology

Using established processes for energy

transfer to compact surface

infrastructure.

Pressurized Water Reactor (PWR)

Commercial PWR using LEU fuel first went

critical in August 1960.

1 Currently 64 PWRs

producing 64 GWe in the U.S.2,3

1Library of Congress

2Nuclear Regulatory Commission

3Energy Information Administration

Deep Fission aims to simplify

nuclear reactor deployment

—

deep underground, designed

to scale.

The goal is to reduce reliance

on surface infrastructure to

advance nuclear power today. 6

Primary Heat

Exchanger

Reactor

Canister

LEU Fuel

Assemblies

Unique

innovations and

novel concepts

Gravity does the work.

40+

Pending patent

applications

26+

Patents issued 3

Passive safety by design.

Large

-diameter borehole is cased and cemented from

surface to total depth of ~6000 ft. Cooling is always

present with the reliability of gravity, eliminating large

break loss

-of

-coolant as a credible accident scenario.

Pressure from a mile

-long water column.

Water pressure at one mile deep is ~160 atm

and the reactor operates at ~160 atm. This

equalization of pressure inside and outside

improves safety of PWR.

Standard nuclear core, made simple.

The reactor uses conventional PWR physics and

LEU fuel, and the heat transfer system consists of

three fully

-isolated, closed loops.

The primary loop transfers heat from the reactor to

a heat exchanger that sits directly above the

reactor.

The secondary loop picks up heat at the downhole

heat exchanger and rises naturally to meet the

steam loop at the surface.

123

Development

is already

underway

Prototype canister

installation demonstrated

2 GWe

Master Energy Purchase

Agreement at Great Plains

~6,000 ft.

first data acquisition well

Targeting six months from

drilling to delivery for one

single NOAK reactor, capable

of powering a neighborhood.

Phased deployment of ten

reactors powers an industrial site.

Minimal surface buildout of five

boreholes per turbine/generator.

100 reactors on a single site can

power a hyperscale campus.

Continuous multi-well execution can

pace deployment with demand.

Our goal is speed at scale:

From drilling to delivery in

months, not years.

15 MWe 2 GWe

150 MWe 1.5 GWe

The most

affordable

way to build is

not to build at all.

Utility-scale solar is ~7,000 acres per gigawatt.

The most recent conventional PWR is ~700 acres per gigawatt.

Deep Fission is designed for ~100 acres per gigawatt.

Conventional Above-Ground Pressurized Water Reactor

X Containment Building

X Pressurizer

X External Backup Power

X External Emergency

Core Cooling Systems

Commercialization

target: up to 5 MWe

by December 2027

à Prove it

• Wellbore Engineering

• Wide-Diameter Drilling

• Feasibility of Design, Construction,

Assembly and Installation

2026: NON-NUCLEAR

à License it

• Safety

• Fuel & Supply Chain

• Operations & Maintenance

2027: NUCLEAR

à Scale it

• Cost

• Deployment Time

• Repeatability

2028: NOAK

2026 2027 2028

S O N D J F M A M J J A S O N D J F M A M J J A

NSDA approval Completed Aug 6, 2026

Prototype PWR run Completed Sep 3, 2026

Multi-reactor license submission

Non-nuclear wellbore construction

DSA submittal

NRC licensing submission

Thermal and instrumentation testing and demo

DOE authorization

Pilot well drilling and completion

LEU fuel fabrication

Reactor delivery and on-site assembly

Pilot Program PWR installation

Pilot demonstration

Surface construction

Turbine/generator delivery

PDSA approval

Long-term fuel partner

Grid interconnection / commercial conversion

NRC commercial license issued

Regulatory Siting Fuel Construction Commercialization Milestones Commercial Operation Date (COD) Target

Completion Date Estimates

Master energy purchase agreement Completed Oct 16, 2026

Liz Muller

CEO & Co-Founder

“Large

diameter

drilling to

these depths

is a method

we’ve refined

since 1971.”

Flooded reverse-circulation drilling Borehole sections 30-60 inches diameter.

Custom large-diameter drill bits Manufacture of project-specific reverse-circulation bits 30-60 in.

Grid-connected electric drilling rig Reduced diesel consumption, onsite

combustion emissions & energy costs.

Custom, precision-controlled

cementing system

Controlled cement placement procedures

between casing & borehole.

Large-diameter well-control equipment

Manage artesian flow & handle large

drilling tools, including the arrangement

described in four US Patents.

Youngquist Technology Deep Fission Application

Harvey Youngquist, CEO

Youngquist Brothers Collaboration:

Advancement and application of technology

and methods for constructing large-diameter

boreholes à

Commercial

drilling at scale:

Financial

catalysts and

key programs

1234

Location Customization

Optimizing the drilling approach to

site geology to achieve high drill

speed (ROP) with limited ris

Design Evolution

Streamlined wellbore architecture

and materials drive down cost

Rig Management Management of our drilling

rig fleet

High Volume

Procurement

Once operating

at 150MW scale,

significant supply chain efficiencies

Build-Own-Operate

Business Model

Project-Level Equity Participation

For certain projects, we plan to retain an ownership

interest in the project company. This would allow us to

benefit from project-level cash flows associated with

electricity generation and sale over the operating life of

the facility, driven by long-term power purchase

agreements or similar offtake arrangements.

Intellectual Property Licensing

& Services

Recurring licensing fees associated with the use of our

proprietary technology, and revenues from long-term

reactor services such as refueling, operations, and

regulatory support.

Illustrative Unit

Economics (NOAK):

Critical Parameters

Power output: up to 15 MWe

Development timeline: Approx. 2 years

Upfront capital cost: $84M at 2024 economics

Run-rate revenue: $20M per year avg. first ten years

Operating cash flow: $10M per year; $600M over project life

Project financing: 60% of upfront capital at 8%

Investment Tax Credits: 30%, monetized at 90%

Optimizes neutron efficiency, thermal transfer and a fuel cycle of 7–10 years

Wide-diameter drilling technology exists today

Less labor-intensive NOAK design, engineering and supplier development;

learning-curve efficiencies; optimized drilling and surface infrastructure

$110 per MWh price point at 2024 economics

Refueling expenses amortized over 7 years; reasonable estimates of O&M

expenses

Project cash flow supports this amount or greater, and project finance leverages

equity returns

Bring in a tax equity partner or monetize directly

RATIONALE & ASSUMPTIONS:

These reactor-level estimates are solely to illustrate certain internal estimates and assumptions used in

developing the Company’s business model and are based on a range of assumptions including, among

others, a 40-year design life; that output achieves target levels (i.e., 15 MWe and 8 MWe for 3x3

configuration and 2x2 configuration, respectively); approximately 93% operation uptime; PPAs for entire

amount of assumed output, at initial pricing of $110 per MWh; that reactor design remains standardized

and repeatable; construction and commissioning periods; and that deployment conditions remain

constant. Actual results may differ materially. See "Cautionary Note on Forward-Looking Statements” on

[slide 3] of this presentation and "Risk Factors-Risks Related to Our Business and Industry" and

"Business-Reactor Architecture" in our Registration Statement on Form S-1 filed with the SEC.

Fuel Manufacturing Engineering

Leveraging mature supply chain

Drilling &

Completion

MOU Signed Designing the

instrument hub +

electronics for

monitoring the

reactor

Enriched uranium

product (EUP)

procured

Engineering,

Procurement,

Construction

manager for the

demonstration

reactor

Delivered the

prototype reactor

Energy Resilience for All

DeepFission.com

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

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Name of the City or Town

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Code for the postal or zip code

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Name of the state or province.

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- Definition

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

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

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

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Indicate if registrant meets the emerging growth company criteria.

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-Name Exchange Act

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-Section 12

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Indicate if an emerging growth company has elected not to use the extended transition period for complying with any new or revised financial accounting standards.

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-Publisher SEC

-Name Securities Act

-Number 7A

-Section B

-Subsection 2

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- 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.

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No definition available.

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

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

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-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

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

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-Publisher SEC

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Local phone number for entity.

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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.

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-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

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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.

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- Definition

Title of a 12(b) registered security.

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-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

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Name of the Exchange on which a security is registered.

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-Section 12

-Subsection d1-1

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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.

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Trading symbol of an instrument as listed on an exchange.

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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.

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-Publisher SEC

-Name Securities Act

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-Section 425

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