Denison Announces at the Market Offering Agreement with Cantor Fitzgerald & Scotia Capital

Denison Mines Corp.

1100 – 40 University Ave

Toronto, ON M5J 1T1

www.denisonmines.com

PRESS RELEASE

DENISON ANNOUNCES AT THE MARKET OFFERING AGREEMENT WITH

CANTOR FITZGERALD & SCOTIA CAPITAL

Toronto, ON – Sept 28, 2021. Denison Mines Corp. (“Denison” or the “Company”) (DML: TSX, DNN:

NYSE American) is pleased to announce that it has entered into an equity distribution agreement dated

September 28, 2021 (the “Equity Distribution Agreement”), providing for an at-the-market (“ATM”) equity

offering program, with Cantor Fitzgerald Canada Corporation (“CFCC”), Scotia Capital Inc. (together with

CFCC, the “Co-Lead Canadian Agents”), Cantor Fitzgerald & Co. and Scotia Capital (USA) Inc. (together

with the Co-Lead Canadian Agents, the “Agents”).

The ATM will allow Denison, through the Agents, to, from time to time, offer and sell, in Canada and the

United States through the facilities of the Toronto Stock Exchange (“TSX”) and/or NYSE American, such

number of common shares as would have an aggregate offering price of up to USD$50 million. Sales of

the common shares, if any, will be made by means of ordinary brokers’ transactions on the TSX and/or

NYSE American or otherwise at market prices prevailing at the time of sale. The ATM will be effective until

October 16, 2023 unless terminated prior to such date by Denison or otherwise in accordance with the

Equity Distribution Agreement.

The Company considers the execution of the Equity Distribution Agreement a routine capital markets

matter, establishing the ATM as a potentially valuable tool for future access to the public market, where

equity offerings can occur at market prices and with significantly reduced costs. The timing and extent of

the use of the ATM will be at the discretion of the Company. Accordingly, total gross proceeds from equity

offerings under the ATM could be significantly less than USD$50 million.

As outlined in the prospectus supplement, the Company intends to use any proceeds from the ATM to fund

its mineral property evaluation and project engineering activities, long lead project construction items as

well as general, corporate and administrative expenses. The actual allocation of the proceeds may vary

depending on the amount of proceeds raised, the time periods in which the proceeds are raised, and the

future developments in relation to the Company’s projects or unforeseen events.

The sale of the Company’s common shares through the ATM will be made pursuant to, and qualified in

Canada by, a prospectus supplement dated September 28, 2021 (“Prospectus Supplement”) to the base

shelf prospectus of the Company dated September 16, 2021 (“Base Prospectus”), and in the United States

pursuant to a prospectus supplement dated September 28, 2021 to the Company’s final base shelf

prospectus contained in the Company’s registration statement Form F-10 (File No. 333-258939) as

amended and declared effective on September 17, 2021 (the “U.S. Registration Statement”) filed with the

United States Securities and Exchange Commission.

Copies of the Prospectus Supplement and Base Prospectus may be obtained for free from SEDAR at

www.sedar.com, and copies of the Prospectus Supplement and U.S. Registration Statement containing the

Base Prospectus may be obtained for free from EDGAR on the SEC website at www.sec.gov. Alternatively,

any of the following Agents participating in the ATM will arrange to send you these documents if you make

a request by contacting:

In the United States:

Cantor Fitzgerald & Co.

Attention: Equity Capital Markets

499 Park Avenue, 6th Floor,

New York, New York, 10022

Email: [email protected]

Scotia Capital (USA) Inc.

Attention: Equity Capital Markets

250 Vesey Street, 24th Floor

New York, New York, 10281

Email: [email protected]

Telephone: 212-225-6853

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In Canada:

Cantor Fitzgerald Canada Corporation

Attention: Equity Capital Markets

181 University Avenue, Suite 1500,

Toronto, ON, M5H 3M7

Email: [email protected]

Scotia Capital Inc

Attention: Equity Capital Markets,

Scotia Plaza, 62nd Floor, 40 King Street West,

Toronto, ON M5H 3Y2,

Email: [email protected]

Telephone: 416-863-7704

The common shares that may be issued by the Company under the ATM have been conditionally approved

for listing on the TSX and have been approved for listing on the NYSE American.

This press release shall not constitute an offer to sell or a solicitation of an offer to buy, nor will there be

any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be

unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Denison

Denison is a uranium exploration and development company with interests focused in the Athabasca Basin

region of northern Saskatchewan, Canada. The Company has an effective 95% interest in its flagship

Wheeler River Uranium Project, which is the largest undeveloped uranium project in the infrastructure rich

eastern portion of the Athabasca Basin region of northern Saskatchewan. Denison's interests in

Saskatchewan also include a 22.5% ownership interest in the McClean Lake joint venture (“MLJV”), which

includes several uranium deposits and the McClean Lake uranium mill that is contracted to process the ore

from the Cigar Lake mine under a toll milling agreement, plus a 25.17% interest in the Midwest Main and

Midwest A deposits, and a 66.90% interest in the Tthe Heldeth Túé (“THT,” formerly J Zone) and Huskie

deposits on the Waterbury Lake property. Each of Midwest Main, Midwest A, THT and Huskie are located

within 20 kilometres of the McClean Lake mill.

Through its 50% ownership of JCU, Denison holds additional interests in various uranium project joint

ventures in Canada, including the Millennium project (JCU 30.099%), the Kiggavik project (JCU 33.8123%)

and Christie Lake (JCU 34.4508%).

Denison is also engaged in mine decommissioning and environmental services through its Closed Mines

group (formerly Denison Environmental Services), which manages Denison's Elliot Lake reclamation

projects and provides post-closure mine care and maintenance services to a variety of industry and

government clients.

For more information, please contact

David Cates (416) 979-1991 ext 362

President and Chief Executive Officer

Shae Frosst (416) 979-1991 ext 228

Investor Relations

Cautionary Statement Regarding Forward-Looking Statements

Certain information contained in this news release constitutes ‘forward-looking information’, within the meaning of the applicable United

States and Canadian legislation concerning the business, operations and financial performance and condition of Denison.

Generally, these forward-looking statements can be identified by the use of forward-looking terminology such as ‘plans’, ‘expects’,

‘budget’, ‘scheduled’, ‘estimates’, ‘forecasts’, ‘intends’, ‘anticipates’, or ‘believes’, or the negatives and/or variations of such words and

phrases, or state that certain actions, events or results ‘may’, ‘could’, ‘would’, ‘might’ or ‘will be taken’, ‘occur’, ‘be achieved’ or ‘has

the potential to’.

In particular, this news release contains forward-looking information pertaining to the following: the ATM and agreements with the

Agents with respect thereto; the use of proceeds of any offerings that may be completed pursuant to the ATM; and expectations

regarding its joint venture ownership interests and the continuity of its agreements with its partners.

Forward looking statements are based on the opinions and estimates of management as of the date such statements are made, and

they are subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity,

performance or achievements of Denison to be materially different from those expressed or implied by such forward-looking

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statements. For example, Denison may decide or otherwise be required to discontinue its field test activities or other testing, evaluation

and development work at Wheeler River if it is unable to maintain or otherwise secure the necessary resources (such as testing

facilities, capital funding, regulatory approvals, etc.) or operations are otherwise affected by COVID-19 and its potentially far-reaching

impacts. Denison believes that the expectations reflected in this forward-looking information are reasonable but no assurance can be

given that these expectations will prove to be accurate and results may differ materially from those anticipated in this forward-looking

information. For a discussion in respect of risks and other factors that could influence forward-looking events, please refer to the

factors discussed in Denison’s Annual Information Form dated March 26, 2021 under the heading ‘Risk Factors’. These factors are

not, and should not be construed as being exhaustive.

Accordingly, readers should not place undue reliance on forward-looking statements. The forward-looking information contained in

this news release is expressly qualified by this cautionary statement. Any forward-looking information and the assumptions made with

respect thereto speaks only as of the date of this news release. Denison does not undertake any obligation to publicly update or revise

any forward-looking information after the date of this news release to conform such information to actual results or to changes in

Denison's expectations except as otherwise required by applicable legislation.