Investor Update - April 2026

Corporate Update

April 2026

Uranium Development & Exploration

The Athabasca Basin, Northern Saskatchewan

#1 Non-Precious Mining

Development Project

in the World

Building the next source of sizeable Western uranium supply

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

• Site preparation & initial construction commenced in March 2026 at flagship Phoenix In-Situ Recovery ('ISR') mine(3)

• Final Investment Decision made shortly after regulatory approvals received to commence construction(3,4)

• Technical de-risking completed; C$60M committed on long-lead procurement(5,6)

• First production targeted by mid 2028(6)

  
  
  

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

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

• Produced 649k lbs U3O8in 2025 (100% basis) at the McClean North deposit following restart in June(7,9)

• Top 5 largest uranium producer in North America in 2025(7,9,10)

  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$700M in cash, physical uranium and investments(7)

• Denison's financial and liquid assets on hand, relative to initial capex(6) for the flagship Phoenix development project 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(8)

3

NOTES: (1) See supporting slides for details. (2) UxC's Uranium Production Cost Study dated Aug. 2025. (3) See news release dated Feb. 24, 2026. (4) See news release dated Feb. 19th, 2026. (5) The amount committed on long lead procurement is a non-GAAP measure and reflects WRJV spend on items reported in property plant and equipment as of Dec. 31, 2025. (6) For additional details see 2026 AIF. (7) As of Dec. 31, 2025. For additional details see financial statements and MD&A for the period ended Dec. 31, 2025 and slide 7 footnote 2. (8) World Nuclear News article dated Nov. 17, 2025. (9) MLJV Production in 2025 on a 100% basis; Denison's share 146klbs U3O8. (10) Based on UxC Q1' 2026 UMO Production Outlook, Company filings.

Multi-asset leverage to uranium market from advanced + diversified Athabasca Basin asset base

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 news release dated Feb. 24, 2026 and Denison's 2026 AIF for details.

3. Phoenix Project - See news release dated Feb. 19, 2026

4. ) Per UxC's Q1' 2026

   Uranium Market Outlook and Cameco's management's discussion and analysis dated Feb. 13, 2026.

5. See news release dated Jul. 17, 2025. For additional details see financial statements and MD&A for the period ended Dec. 31, 2025

6. MLJV Production in 2025 on a 100% basis; Denison's share 146klbs U3O8

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 Dec. 31, 2025; excludes the land positions held by JCU.

4

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

Sample of Global Production Costs - August 2025(1)(2)(3)(4)(5) 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 to ~US$97.51/lb U3O8)

$18.41 (2026)

$24.93 (2020)

$25.47 (2023)

$25.78 (2025)

$80

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

$70

$60

$50

$40

$30

ISR ISR ISR

ISR

UG UG UG UG ISR

UG ISR UG

ISR

$20

UG OP OP OP ISR ISR ISR SAB

OP

$10

$0

Denison/Canada (UxC Est.)

Canada

Kazakhstan

Australia

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

Waterfound (Denison 24.68%)(2)

Johnston Lake (Denison 100%)

McArthur River Mine

Rabbit Lake Mill

Cigar Lake Mine

Wheeler North

(Denison 49%)(3)

Wheeler River (Denison 95%)(2)

NOTES:

7

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

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. Refer to Denison's AIF dated Mar 30,2026 for details.

5. See news release dated Feb 19, 2026.

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

7. As of Dec. 31, 2025. For additional details see financial statements and MD&A for the period ended Dec. 31, 2025.

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

   Nov. 22, 2022.

9. Pheonix Capex. See Denison's current AIF for details.

8

Phoenix Project Execution Progressing

De-risking complete and site preparation in progress

PHOTO:

View of new SaskPower 138kV Transmission Line to

Significant

De-risking and Engineering to Position for Execution

• High-grade, low-cost project justified technical studies and extensive test work, detailed engineering, permitting + team building during period prior to improved uranium market

• Total engineering ~87% complete, including most scopes planned for the first year of construction at 100% total engineering(1,2)

• Grid power, with SaskPower line completed to Phoenix(3)

• Construction management contract awarded to Wood Canada Limited(4)

  Leading

  Permitting & Community Engagement

  • Final Federal regulatory approval received to construct the Phoenix ISR Uranium Mine, with CNSC approval of the EA, and Licence to Prepare Site and Construct a Mine and Mill(5)

  • Received Saskatchewan EA approval for Phoenix, harmonized with federal EA and CNSC approval(5)

  • Multiple impact-benefit type agreements with Indigenous nations and northern communities, plus leading engagement practices(7)

    Procurement

    Advancing & Site Preparation Commenced

  • Site preparation and initial construction underway at Phoenix with construction management project team and initial work crews mobilized to site and remaining key contract awards expected by mid-2026(2)

  • Final Investment Decision completed shortly after receipt of final regulatory approvals for construction

  • Project timeline on track for targeted first production by mid-2028

    Robust

    Balance Sheet

    • Strong Balance Sheet to fund construction with ~CAD$700M

      in cash, physical uranium and investments(1)

    • Physical uranium holdings intended to support project financing and offer significant financial flexibility(1)

      the site of the Future Phoenix Uranium Mine.

      NOTES:

      1. For additional details see financial statements and MD&A for the period ended Dec. 31, 2025. Includes 1.7Mlbs of purchased physical U3O8and 146klbs of finished goods from Denison's share of McClean North production. Current finished goods inventory from McClean North production valued using

         the prevailing market price as of Dec. 31,2025, the same value per pound as purchased physical U3O8. The balance sheet carries finished goods inventory from McClean North production at cost.

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

      3. See news release dated Jan. 8 2026.

      4. See news release dated Feb. 17, 2026

      5. See news release dated

         Feb. 19, 2026

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

         Commercial Strategy Aligned with Project Financing Objectives and Asset Base

         • Existing agreements to sell >5Mlb U3O8and advanced negotiations in progress for further sales of 12Mlb U O (1)

2024, and Oct. 20, 2022,

3 8 and MD&A for the period

• Multiple sources of supply is a differentiator: Physical U3O8, McClean Lake North production, & future Phoenix production

ended Dec. 31, 2022.

9

Construction teams and equipment have mobilized to site

10

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

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 Denison's AIF dated

   Mar. 30, 2026 for details.

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 Denison's AIF dated Mar. 30, 2026 for 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 AIF dated Mar. 30, 2026 for details.

6. Refer to slide 9 for further information regarding Phoenix Capital Expenditure Estimates.

11

Optimized production profile based on detailed ISR mine planning efforts

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 Denison's AIF dated Mar. 30, 2026; (3) See press release Feb. 24, 2026; (4) NPV and IRR are calculated to the start of construction activities for the Phoenix operation and excludes $100 million in pre-FID expenditures; (5) Payback period is stated as number of months to payback from the start of uranium production.

12

Provides Denison with additional source of low-cost production to reinvest Phoenix cash flows(1)

PHOTO:

View inside the SX circuit at Denison's 22.5% owned McClean Lake mill, which is assumed to toll mill production from the Gryphon UG operation.

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. NPV and IRR are calculated to the start of pre-production activities for the Gryphon operation.

3. 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. See Wheeler River Technical Report and Denison's news release dated Jun. 26, 2023 for details.

13

Capital and operating costs updated from 2018 PFS + minor scheduling optimizations

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) NPV and IRR are calculated to the start of construction activities for the Gryphon operation, and excludes $56.5 million in pre-FID expenditures; (3) Payback period is stated as number of months to payback from the start of uranium production; (4) Post-tax NPV is estimated to be $864.2 million in the Base Case; (5) Post-tax payback period is estimated to be 23 months in the Base-Case; (6) Post-tax IRR is estimated to be 37.6% in the Base Case.

14

Strategic asset uniquely positioned to support new sources of supply from JV owners

PHOTO:

Aerial view of Denison's 22.5% owned McClean Lake mill facility.

NOTES:

1. Per UxC's Q1' 2026

   Uranium Market Outlook and Cameco's management's discussion and analysis dated Feb. 13, 2026.

2. See Denison's news release dated Jan. 19, 2022.

3. Denison monetized its share of tolling revenues from the Cigar Lake toll milling agreement. See Denison's news releases dated Feb. 1, 2017 and

   Feb. 13, 2017. Please also refer to Denison's current Annual Information Form and Financial Statements and Management, Discussion and Analysis for additional details related to the toll milling agreement.

4. See Denison's current Annual Information Form for additional details regarding the McClean Lake mill facility.

15

Mining restart achieved via SABRE mining method at McClean North deposit

McClean Lake JV production (100% basis) (1)

~US$26/lb

Operating Cash Costs

2025 MLJV production

(100% basis)(1)

PHOTO:

2021 SABRE test mining program in action, with view of specialized mining pipes in inset photo.

NOTES:

1. As of Dec. 31, 2025,

   100% basis. See Denison's financial statements and MD&A for the year ended Dec. 31, 2025 for details.

2. See Denison's current AIF for additional details regarding the McClean Lake deposits and SABRE mining method.

3. See Denison's financial statements and MD&A for the year ended Dec. 31, 2025 for details.

4. See Denison's current

   AIF for additional details.

5. See Denison's news releases dated Sept. 8, 2022 and Jul. 21, 2025.

16

In-Situ Recovery PEA for Midwest Main leverages high-grades & proximity to McClean mill(1)

PHOTO:

Aerial view of Midwest Project.

NOTES:

1. See Denison's news release dated Aug. 6, 2025.

2. See Denison's current Annual Information Form for additional details regarding the Midwest project.

3. NPV and IRR are calculated to the start of construction activities for the Midwest project and excludes the C$16.8M in pre-FID expenditures.

4. 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.

17

Demonstrates economic and technical potential at the Midwest Main deposit

7,000,000

6,000,000

Pounds U3O8per year

5,000,000

4,000,000

3,000,000

Midwest mine production per year

2,000,000

1,000,000

-

Calendar Years

Production lbs U3O8

1 2 3 4 5 6 7

6.1M 6.1M 6.1M 6.1M 6.1M 6.1M 0.8M

NOTES: (1) Refer to Denison's news release dated Aug. 6, 2025; (2) NPV and IRR are calculated to the start of construction activities for the Midwest project and excludes $16.8 million in pre-FID expenditures; (3) Payback period is stated as number of months to payback from the start of uranium production; (4) Post-tax NPV is estimated to be $964.7.2 million in the Base Case; (5) Post-tax payback period is estimated to be ~9 months in the Base-Case; (6) Post-tax IRR is estimated to be 82.7% in the Base Case.

18

PEA (2020) shows potential for ISR to change uranium mining landscape in Canada(1)

PHOTOS:

Aerial rendering of surface facilities for the THT ISR operation

NOTES:

1. 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.

2. See Denison's news

release dated Nov. 6, 2023

1. All-in cost is estimated on a pre-tax basis and includes all project operating costs and capital costs divided by the estimated number of finished pounds U3O8produced.

2. NPV and IRR are calculated based on assessed "high-case" uranium price, to the start of pre-production activities.

3. Post-tax NPV attributable to Denison's then 66.90% interest is estimated to be between

   $72 million (base-case) and $109 million ($65/lb high-case).

4. Post-tax IRR attributable to Denison's then 66.90% interest is estimated to be between 30.4% (base-case) and

38.9% ($65/lb high-case).

19

Strengthening exposure to exploration upside through strategic investment

(9) As of December 31, 2025. See Denison's Q4 2025 MD&A for more information. 20

World