Denison Mines Corp.TSX: DML

Investor Update - January 2026

· Issued by Denison Mines Corp.

Corporate Update

January 2026

Uranium Development & Exploration

The Athabasca Basin, Northern Saskatchewan

#1 Non-Precious Mining Development Project in the World




Key Investment Highlights(1):

Advanced Athabasca Basin uranium developer with unique asset mix

Portfolio of four low-cost uranium development projects

  • Phoenix, Gryphon, Midwest and THT/Waterbury all projected within UxC's "First Tier" of global assets(2)

    Phoenix combines lowest-cost mining method with Athabasca Basin high-grades #1

  • Ranked #1 non-precious mining development project globally in 2025 by Mining Journal Intelligence

  • Flagship In-Situ Recovery ('ISR') project with final federal Environmental Impact Statement accepted by Canadian Nuclear Safety Commission ('CNSC') and Provincial EA Approval received

  • Technical de-risking completed; C$47M spent on long-lead procurement(3,5)

  • First production targeted by mid 2028 (5)



    Ownership interest in strategic regional asset with McClean Lake mill and producing mine

  • Excess licensed milling capacity, with approval for expanded tailings management facility

  • Announced 2025 mining restart at McClean North deposit by Orano Canada

    High-potential exploration portfolio and interests in key mines / projects operated by "majors"

  • Large Athabasca Basin exploration portfolio, including Moon Lake South and Johnston Lake properties

  • Minority interests in Cameco-JCU's Millennium project and Orano-JCU's Kiggavik project



    Strong balance sheet with ~C$718M in cash, physical uranium and investments(4)

    3

  • Denison's financial and liquid assets on hand, relative to initial capex(5) for the flagship Phoenix development project (C$570M for Denison's effective 95% interest) puts the company in a strong position

Focused on the infrastructure-rich Eastern Athabasca Basin in Saskatchewan, Canada Nuclear energy commitments: 30+ nations pledge to triple nuclear energy capacity by 2050(6)

NOTES: (1) See supporting slides for details. (2) UxC's Uranium Production Cost Study dated Aug. 2025. (3) The amount spent on long lead procurement is a non-GAAP measure and reflects spend on items reported in property plant and equipment as of November 30, 2025. (4) As of Sep. 30, 2025. For additional details see financial statements and MD&A for the period ended Sep. 30, 2025. (5) See news release dated Jan. 2, 2026. (6) World Nuclear News article dated November 17, 2025.

Diversified Athabasca Basin asset base with superior development leverage

95%(1)

effective interest in

Flagship

Wheeler River project

Development-stage project (Phoenix + Gryphon deposits)

Largest Mineral Reserves of undeveloped uranium projects in the infrastructure rich eastern Athabasca Basin

2023 Phoenix Feasibility Study(2)

Final Environmental Impact Statement accepted by CNSC and received Provincial EA Approval(3,4)

22.5%

interest in

Strategic McClean Lake Uranium mill & mines

~11% of global uranium production processed through mill(5)

Mining restarted June 2025 using SABRE mining at McClean North deposit(6)

Excess licensed milling capacity

25.17%

interest in

High-grade Midwest project close to McClean mill

2025 Preliminary Economic Assessment ('PEA') for ISR mining at Midwest Main deposit(7)

High-grades and close proximity to the McClean Lake mill support robust PEA economics

Also being evaluated for potential development with SABRE mining method

70.55%

interest in

Well-situated Waterbury Lake project

PEA stage development project for ISR mining proximal to McClean mill(8)

Tthe Heldeth Túé ('THT') deposit highlights potential for future development project pipeline(8)

Successful completion of 2023 ISR field test(9)

50% ownership of JCU(10), adding portfolio of interests including sizeable share of development-stage assets operated by "majors"

JCU holds various Athabasca Basin exploration project interests, plus 30.099% in Millennium (Cameco) and 33.8118% in Kiggavik (Orano)

~384,000

hectares of exploration ground(11)

NOTES:

  1. Denison's effective interest in Wheeler River includes 90% held directly and 5% held indirectly through its 50% ownership of JCU (Canada) Exploration Company, Limited.

  2. See the Wheeler River Technical Report titled "NI 43-101 Technical Report on

    the Wheeler River Project, Athabasca Basin, Saskatchewan, Canada" dated Jun. 23, 2023.

  3. See news release dated Nov. 25, 2024 and the Canadian Impact Assessment Registry.

  4. See news release dated Aug. 5, 2025.

  5. Derived from UxC's Uranium Market Outlook dated Q3'2025.

  6. See news release dated Jul. 17, 2025.

  7. See news release dated Aug. 6, 2025.

  8. Refer to the Waterbury Lake Technical Report titled "Preliminary Economic Assessment for the Tthe Heldeth Túé (J Zone) Deposit, Waterbury Lake Property, Northern Saskatchewan, Canada" dated Oct. 30, 2020.

  9. See news release dated Nov. 6, 2023.

  10. See news release dated Aug. 3, 2021.

  11. Denison direct land position shown as of Sept. 30, 2025; excludes the land positions held by JCU.

4



Denison's Development Portfolio Projects:

Four assets amongst the lowest all-in cost assets of UxC's First Tier

Sample of Global Production Costs - August 2025 (1)(2)(3)(4)

Planned and Producing Operations (with Mining Method)

UxC's "First Tier"

(includes lowest-cost projects with full costs up to ~US$37.50/lb U3O8)

"Second Tier"

(up to ~US$50.01/lb U3O8)

"Third/Fourth Tier"

(up O )

to ~US$97.51/lb U3

8

$18.41 (2026)(2)

$24.93 (2020)

$25.47 (2023)

$25.78 (2025)



$80

All-in / Full Costs - USD$/lb U3O8

$70

$60

$50

$40

$30

$20

ISR ISR ISR ISR UG UG UG

UG ISR UG ISR

UG

ISR

UG OP OP OP ISR ISR ISR OP

OP

$10

$0





Denison/Canada (Technical Reports)

Denison/Canada (UxC Est.)

Canada

Kazakhstan

Australia

  1. Africa

    ISR: In-Situ Recovery UG: Underground OP: Open Pit

    NOTES:

    1. Chart data, including "full costs" and UxC's categorization of production cost "tiers", have been derived from UxC's estimates of worldwide production costs from the Uranium Production Cost Study dated Aug. 2025.

    2. For Phoenix and Gryphon, see the Wheeler River Technical Report titled "NI 43-101 Technical Report on the Wheeler River Project, Athabasca Basin, Saskatchewan, Canada" dated Jun. 23, 2023 and Denison's news release on Jun. 26, 2023. Phoenix all-in costs reflects updated initial capital, refer to Denison's news release dated Jan. 2, 2026

    3. For THT/Waterbury, refer to the Waterbury Lake Technical Report titled "Preliminary Economic Assessment for the Tthe Heldeth Túé (THT) (J Zone) Deposit, Waterbury Lake Property, Northern Saskatchewan, Canada" dated Oct. 30, 2020 and Denison's news release on Nov. 17, 2020.

    4. For Midwest, refer to Denison's news release dated Aug. 6, 2025.

    5



    Large land position in the infrastructure-rich eastern portion of the Athabasca Basin(1)

Midwest (Denison 25.17%)

Waterbury Lake (Denison 70.55%)

McClean Lake Mill (Denison 22.5%)

McClean Lake North (Denison 22.5%)

Moon Lake South (Denison 75%)

All Season Highway

/ Haul Road

Waterfound (Denison 24.68%)(2)

Johnston Lake (Denison 100%)

McArthur River Mine

Wheeler River (Denison 95%)(2)

Provincial Power Grid

Key Lake Mill

Rabbit Lake Mill

Cigar Lake Mine

NOTES:

  1. Denison direct land position shown as of Sept. 30, 2025 and pro forma for the completed transaction with Skyharbour Resources. For more information see news release dated Dec. 17, 2025.

  2. Denison's effective interest in Wheeler River includes 90% held directly and 5% held indirectly through its 50% ownership of JCU (Canada) Exploration Company, Limited.

6



Robust Balance Sheet with ~CAD$718M(1)in cash, physical uranium and investments

1.9M lbs U3O8

in holdings of physical uranium(1)

Market value ~CAD$217M (US$82.00/lb U3O8)(1) Acquired at average cost of USD$29.70/lb U3O8(1)

Long-term holding expected to support project financing for flagship Wheeler River Project(2)

All material received and held in licenced North American storage facilities (Cameco + ConverDyn)

CAD$471M

in

cash and cash equivalents(1)

CAD$30M

investments in

uranium equities and

convertibles held by Denison(3)

USD$345M

issuance of

2031

convertible notes

Capped call increases effective conversion premium to 100% of share price on the pricing date of the offering(4,5)

Balance sheet position, relative to initial project capex for flagship development asset (Phoenix), is strong among uranium development-stage peers

NOTES:

  1. As of Sept. 30, 2025. For additional details see financial statements and MD&A for the period ended Sept. 30, 2025.

  2. See Denison's news releases dated Mar. 15, 2021,

    Mar. 22, 2021, and Apr. 1,

    2021.

  3. As of Sept 30 2025, for additional details see financial statements and MD&A for the period ended Sept. 30, 2025; includes investments in uranium equities and convertible debentures held by Denison.

  4. Gross proceeds of convertible note offering. For more details please see Denison's press release dated Aug. 15, 2025.

  5. The company has no other debt drawn as of Sept 30, 2025; however, the company has a letters of credit facility in place that is used to secure reclamation letters of credit, as more fully described in the financial statements and MD&A for the period ended Sept. 30, 2025.

7



95% owned flagship Wheeler River project(1)(2)

Two

premier and viable development assets

Phoenix - In-Situ Recovery ("ISR") operation with on-site processing to finished U3O8

Gryphon - contributes additional production via conventional underground mining with assumed toll milling at 22.5% Denison owned McClean Lake mill

~16.5 years

Aggregate operating

Mine life(3)

CAD$600M

Estimated (100% basis)

Initial CAPEX (Phoenix) (9)

Phoenix advancing towards final investment decision

Provincial EA approved(6)

EIS accepted as final by CNSC(4)

Final CNSC Hearing completed in Dec. 2025(9) Total engineering ~87% complete(9)

Rigorous multi-year technical de-risking

2022 Feasibility Field Test successfully recovered uranium bearing solution(8)

Gryphon expected to be funded from internal cash flows

Phoenix cash flow expected to fund Gryphon CAPEX

Project benefits from existing or planned Denison-owned infrastructure

106.4M lbs U3O8

(combined, 100% basis)(1)

Proven & Probable Reserves

2-year Construction

Planned construction period

for Phoenix prior to first production(9)

Mid-2028

Planned Production Start-up for Phoenix(9)

Potential to Deliver Meaningful Production When the Market Needs It

NOTES:

  1. Refer to the Wheeler River Technical Report titled "NI 43-101 Technical Report on the Wheeler River Project, Athabasca Basin, Saskatchewan, Canada" dated Jun.

    23, 2023.

  2. Denison increased its effective interest in Wheeler River as part of the acquisition of 50% of JCU (Canada) Exploration Company, Limited. See Denison's news release dated Aug. 3, 2021.

  3. Reflects 10-year mine life estimated for Phoenix and 6.5-year mine life estimated for Gryphon.

  4. See news release dated Nov. 25, 2024 and Canadian Impact Assessment Registry.

  5. See news release dated Feb. 27, 2025 and Canadian Impact Assessment Registry.

  6. See news release dated Aug. 5, 2025.

  7. As of Sept. 30, 2025. For additional details see financial statements and MD&A for the period ended Sept. 30, 2025.

  8. See news releases dated Oct. 17, 2022 and

    Nov. 22, 2022.

  9. See news release dated Jan. 2, 2026.

8



Phoenix In-Situ Recovery ("ISR") Feasibility Study (2023)(1):


Reflects rigour of multi-year technical de-risking and delivers impressive economic results

#1 Non-Precious Mining Development Project in the World(3)

70.5M

lbs U3O8

@

11.4%

U3O8

Measured & Indicated Mineral Resources

(280,200 tonnes,

100% basis)

One of the highest-grade undeveloped uranium deposits globally

C$1.57B

estimated

Base-case

post-tax NPV8%

(100% basis)(4)

C$600M

Updated 2026

Initial CAPEX(2)

(100% basis)

73%

estimated

Base-case post-tax IRR(4)

2.6 to 1

Base-case post-tax NPV

to initial capital cost ratio(2)

Including…

56.3M

lbs U3O8

@ 46.0% U3O8

M&I mineral resources for Zone A high-grade domain

US$6.28

/ lbs U3O8

average

Cash Operating Costs

(C$8.51/lb U3O8)

US$18.41

/ lbs U3O8

average

All-in Cost(5)

(C$24.92/lb U3O8)



PHOTOS:

Phoenix Feasibility Field Test (FFT) facilities during operations in 2022.

NOTES:

  1. See the Wheeler River Technical Report titled "NI 43-101 Technical Report on

    the Wheeler River Project, Athabasca Basin, Saskatchewan,

    Canada" dated Jun. 23, 2023.

  2. See news release dated Jan. 2, 2026.

  3. Mining Journal Project Pipeline Handbook 2025

  4. NPV and IRR are calculated to the start of construction activities for the Phoenix operation and excludes $100 million in pre-FID expenditures. Post-tax NPV, IRR and payback period are based on the "adjusted Post-tax" scenario, which includes the benefit of entity level tax attributes which are expected to be available and used to reduce taxable income from the Phoenix operation. See January 2, 2026 press release for further details.

  5. All-in cost is estimated on a pre-tax basis and includes all project operating costs, capital costs post-FID, and decommissioning costs divided by the estimated number of pounds U3O8to be produced. Includes updated initial capital costs (2026). See Wheeler River Technical Report and Denison's news release dated Jan. 2 2026 for details.

9





Phoenix ISR Feasibility Study (2023) with 2026 Capex Update(1):

Optimized production profile based on detailed ISR mine planning efforts

56.7 million lbs U3O8 in proven and probable reserves (219,000 tonnes at 11.7% U3O8)

First production targeted by mid 2028(2)

Planned 2-year construction period

Robust economics

2026 Capex Update reflects inflation + construction ready project plans(2)



Assumptions / Results(1,2)

Base Case

$100/lb Case(2)

Selling price / lb U3O8

US$68.89-US$78.36

US$100.00

USD:CAD FX Rate

1.35

1.35

Post-tax NPV (2,3)

8%

(100%)

$1.57 billion

$2.35 billion

Change from 2023 FS

+1%

+51%

Post-tax payback period(2,4)

~12 months

~10 months

Post-tax IRR(2,3)

73%

94%

NOTES: (1) Refer to the Wheeler River Technical Report titled "NI 43-101 Technical Report on the Wheeler River Project, Athabasca

Basin, Saskatchewan, Canada" dated Jun. 23, 2023; (2) Refer to the press release titled "Denison Reports Readiness to Commence Construction of Flagship Phoenix ISR Project and Provides Capital Cost Update" dated Jan 2,2026; (3) NPV and IRR are calculated to the start of construction activities for the Phoenix operation, and excludes $100 million in pre-FID expenditures; (4) Payback period is stated as number of months to

payback from the start of uranium production. 10

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