Not for release to United States news wire services or for dissemination in the United States

Treasury Offering of C$136.5 Million (~ A$141 Million)
Secondary Offering of C$272.5 Million (~ A$282 Million)

• Marimaca and the Selling Shareholders have received strong commitments via the Canadian
  Offering and Australian Offering (defined below)
• Pro forma cash before transactions costs is C$227 million (~ A$235 million¹)²

Vancouver, B.C., February 18, 2026 – Marimaca Copper Corp. (TSX: MARI) (ASX: MC2) (“Marimaca” or the
“Company”) is pleased to announce a highly successful equity bookbuild with strong support from new and existing
shareholders. The proceeds of the Canadian Treasury Offering (the “Canadian Treasury Offering”) will be used to
advance the Marimaca Project and expand the exploration programs at Pampa Medina.

Global Offering Details

The global offering will be completed in two parts (together the “Global Offering”), comprising:

• Canadian Offering:
  • Canadian Treasury Offering: C$136.5 million treasury offering of 13,650,000 common shares of the Company (the “Common Shares”) priced at C$10.00 per Common Share (the “Canadian Issue Price”); and
  • Canadian Secondary Offering: C$120.5 million secondary offering of 12,049,087 existing Common Shares at the Canadian Issue Price owned and controlled by Greenstone Resources II L.P. and Greenstone Co-Investment No. 1 (Coro) L.P. (the “Greenstone Group”).
• Australian Offering:
  • Australian Secondary Offering: A$157 million secondary offering of CHESS Depositary Interests
    of the Company (the “CDIs”) at a price of A$10.35 per CDI (the “Australian Offer Price”) owned and
    controlled by Greenstone Resources II L.P. and other shareholders (together with the Greenstone
    Group, the “Selling Shareholders”).

The Canadian Treasury Offering represents aggregate gross proceeds to the Company of approximately C$136.5
million, or A$141 million¹. The Canadian Secondary Offering and Australian Secondary Offering (together, the
“Secondary Offering”) combined represent aggregate gross proceeds to the Selling Shareholders of approximately
C$272.5 million, or A$282 million¹.

Completion of the Canadian Treasury Offering is subject to TSX approval. The CDIs under the Australian Offering will
be issued pursuant to the ASX Listing Rule 7.1 waiver granted to the Company.

¹ Based on an AUD.CAD exchange rate of 0.9661.
² Cash at February 17, 2026 plus gross proceeds anticipated from the Global Offering.

Canadian Offering

Marimaca has entered into an agreement with the Canadian Co-Lead Agents (defined below), to conduct, on a
commercially reasonable efforts agency basis, a public offering of Common Shares. The Canadian Offering consists
of a Canadian Treasury Offering of Common Shares of the Company for C$136.5 million and a Canadian Secondary
Offering of existing Common Shares, owned and controlled by the Greenstone Group, for C$120.5 million. Collectively,
the Canadian Offering will consist of 25,699,087 Common Shares at the Canadian Issue Price for aggregate gross
proceeds of C$257 million.

The Canadian Offering will be made by way of a prospectus supplement (the “Prospectus Supplement”) to the
Company’s short form base shelf prospectus dated January 9, 2026 (the “Shelf Prospectus”) to purchasers in all of
the provinces and territories of Canada (other than Québec and Nunavut) and may be offered in the United States to
“qualified institutional buyers” under the United States Securities Act of 1933 (“QIBs”), as amended (the “U.S.
Securities Act”) and in those jurisdictions outside Canada and the United States pursuant to exemptions from
prospectus and registration requirements.

Access to the Prospectus Supplement, the Shelf Prospectus and any amendment to such documents is provided in
accordance with securities legislation relating to the procedures for providing access to a shelf prospectus
supplement, a base shelf prospectus and any amendment. The Shelf Prospectus is, and the Prospectus Supplement
will be filed and accessible on SEDAR+ at www.sedarplus.ca on or before February 19, 2026. An electronic or paper
copy of the Prospectus Supplement, Shelf Prospectus, and any amendment to such documents may be obtained,
without charge, from Beacon Securities Limited at [email protected], BMO Capital Markets at
Brampton Distribution Centre C/O The Data Group of Companies, 9195 Torbram Road, Brampton, Ontario, L6S 6H2
by telephone at 905-791-3151 Ext 4312 or by email at [email protected]., by providing the contact
with an email address or address, as applicable.

Australian Offering

Marimaca has entered into an agreement with the Joint Lead Managers (defined below) to complete a brokered
placement of CDIs. The Australian Offering consists of an Australian Secondary Offering of existing CDIs, owned and
controlled by certain Selling Shareholders, for A$157 million.

The CDIs will be offered in Australia to professional investors or sophisticated investors who are also “wholesale
clients” (within the meaning of sections 708(11), 708(10), 708(8) and 761G of the Australian Corporations Act
respectively); in the United States to QIBs and Eligible US Fund Managers; and outside Australia and the United
States to certain institutional, sophisticated or professional investors in Bermuda, Brazil, Cayman Islands, European
Union (excluding Austria), Hong Kong, New Zealand, Malaysia, Norway, Singapore, South Africa, Switzerland, Israel,
United Arab Emirates (excluding financial centres), and United Kingdom.

Retained Interest

Prior to the closing of the Global Offering, the Greenstone Group owns and controls 14,304,285 Common Shares
and 8,000,000 CDIs, representing approximately 18.58% of the Company’s issued and outstanding Common Shares
and CDIs (in aggregate). Following the closing of the Global Offering, assuming it is fully subscribed, the Greenstone
Group will beneficially own and control 2,255,198 Common Shares and 6,351,806 CDIs, representing 6.44% of the
outstanding Common Shares and CDIs (in aggregate) and a decrease in ownership and control by the Greenstone
Group of 13,697,281 Common Shares and CDIs (in aggregate).

As part of the Global Offering, the Selling Shareholders have agreed, subject to certain limited exceptions, not to sell
any Common Shares or CDIs for a 90 day period.

Use of Funds

The net proceeds from the Canadian Treasury Offering will be used to advance the Marimaca Project, including
funding the pre-construction decision engineering workstreams and early site works, to conduct a drilling campaign
at Pampa Medina and for working capital and general corporate purposes.

The net proceeds of the Secondary Offering will be payable to the Selling Shareholders. The Company will not receive
any proceeds from the Secondary Offering.

Indicative Timetable

An indicative timetable for the Global Offering is included below:

(*) Due to time zone difference between Sydney (AEST) and Toronto (EST), the trading halt on the ASX will be lifted prior to 10am AEST on
Thursday, February 19 or 7pm EST on Wednesday, February 18.

The dates and times noted above are indicative only and subject to change. Any material changes will be notified by
the Company to the TSX and ASX, as required. The Company reserves the right to amend any or all of the above
dates and times.

Agents

Beacon Securities Limited and BMO Capital Markets are acting as co-lead agents and joint bookrunners (the
“Canadian Co-Lead Agents”) and co-managed with National Bank Financial Inc., on behalf of a syndicate of agents
(the “Agents”) for the Canadian Offering.

Euroz Hartleys Limited and Canaccord Genuity (Australia) Limited (the “Australian Co-Lead Agents” and, together
with the Canadian Co-Lead Agents, the “Joint Lead Managers”) are acting as lead managers and joint bookrunners
for the Australian Offering.

U.S. Securities Act Disclaimer

The securities under the Canadian Offering and the Australian Offering have not been, and will not be, registered
under the U.S. Securities Act or the securities laws of any state of the United States and may not be offered, sold or
delivered, directly or indirectly, in the United States (as such term is defined in Regulation S under the U.S. Securities
Act), except pursuant to an exemption from the registration requirements of the U.S. Securities Act and applicable
state securities laws. This news release does not constitute an offer to sell or solicitation of an offer to buy any of
these securities in the United States or in any jurisdiction in which such offer, solicitation or sale is not permitted.

About Marimaca

Marimaca is a copper exploration and development company focused on its 100%-owned flagship Marimaca Copper
Project and surrounding exploration properties located in Antofagasta Region, Chile.

The Marimaca Copper Project hosts the Marimaca Oxide Deposit (the “MOD”), an IOCG-type copper deposit. The
Company is currently progressing the Marimaca Copper Project through detailed engineering and submission for
sectorial permits following the release of the 2025 MOD DFS and receipt of the RCA. In parallel, the Company is
exploring its extensive land package in the Antofagasta region, including the >15,000ha wholly-owned Sierra de
Medina property block, located 25km from the MOD. The Company is currently completing a Phase II drilling program
(30,000m) at Pampa Medina, located in the Sierra de Medina property, after a successful discovery drilling program
in 2025 identified a high-grade sedimentary horizon at depth.

This news release is authorized for release by the Board of Directors of Marimaca.

Contact Information

For further information please visit www.marimaca.com or contact:

Tavistock
+44 (0) 207 920 3150
Emily Moss
[email protected]

Forward-Looking Statements
This news release includes certain “forward-looking statements” under applicable Canadian securities legislation,
including statements related to the anticipated participation in and size of the Canadian Offering or Australian Offering,
anticipated timing and closing date of the Canadian Offering or Australian Offering, advisory fees payable, the use of
proceeds and receipt of regulatory approvals and other approvals, including approval of the TSX. There can be no
assurance that such statements will prove to be accurate and actual results and future events could differ materially
from those anticipated in such statements. Forward-looking statements reflect the beliefs, opinions and projections
on the date the statements are made and are based upon a number of assumptions and estimates that, while
considered reasonable by Marimaca, are inherently subject to significant business, economic, competitive, political
and social uncertainties and contingencies. Many factors, both known and unknown, could cause actual results,
performance or achievements to be materially different from the results, performance or achievements that are or
may be expressed or implied by such forward-looking statements and the parties have made assumptions and
estimates based on or related to many of these factors. Such factors include, without limitation: risks related to the
receipt of required regulatory approvals, including timing of approval by the TSX, risks related to share price and
market conditions, the inherent risks involved in the mining, exploration and development of mineral properties, the
uncertainties involved in interpreting drilling results and other geological data, fluctuating metal prices, the possibility
of project delays or cost overruns or unanticipated excessive operating costs and expenses, uncertainties related to
the necessity of financing, uncertainties relating to regulatory procedure and timing for permitting reviews, the
availability of and costs of financing needed in the future. The intended use of the proceeds of the Global Offering by
the Company might change if the board of directors of the Company determines that it would be in the best interests
of the Company and amounts actually allocated and spent will depend on a number of factors, including the
Company’s ability to execute on its business plan. Many of these risks and uncertainties and additional risk factors
generally applicable to the Company are described in the Company’s annual information form of the Company dated
March 27, 2025 and other filings made by the Company with the Canadian securities regulatory authorities (which
may be viewed at www.sedarplus.ca). Accordingly, readers should not place undue reliance on forward-looking
statements. The Company undertakes no obligation to update publicly or otherwise revise any forward-looking
statements contained herein, whether as a result of new information or future events or otherwise, except as may be
required by law.

None of the TSX, ASX or the Canadian Investment Regulatory Organization accepts responsibility for the
adequacy or accuracy of this release.

Legal/94646587_6