Mr. Carl Hansen reports

ATERRA METALS ANNOUNCES UPSIZE OF BROKERED LIFE OFFERING TO $8,355,000

Aterra Metals Inc. has entered into an amended agreement with Research Capital Corp. as the lead agent and sole bookrunner, on behalf of a syndicate of agents including Desjardins Capital Markets, to increase the size of its previously announced brokered, best effort listed issuer financing exemption private placement offering of common shares of the company at a price of six cents per common share for a minimum of $4-million and a maximum of $8,355,000 in aggregate gross proceeds.

The company intends to use the net proceeds of the offering to advance the phase 2 exploration program at its Totora copper-gold project, located in the Dos Amigos mining district in Region III, Chile, and for general working capital and corporate purposes.

On Sept. 24, 2026, Aterra announced a maiden inferred mineral resource estimate for Totora of 159.8 million tonnes grading 0.51 per cent copper equivalent, comprising 0.30 per cent copper and 0.15 gram per tonne gold, based on a 0.2-per-cent copper cut-off grade. The phase 2 program is expected to include infill drilling aimed at increasing confidence in the current inferred mineral resource, resource expansion drilling, and further evaluation of grassroots exploration targets within the Totora project area using geophysics and, where warranted, diamond drilling. The company also intends to commence a program of preliminary metallurgical testwork as part of the phase 2 program.

The common shares will be offered for sale pursuant to the listed issuer financing exemption under Part 5A of National Instrument 45-106 (Prospectus Exemptions), as amended by CSA Coordinated Blanket Order 45-935 (Exemptions from Certain Conditions of the Listed Issuer Financing Exemption), in all provinces of Canada, except Quebec, and other qualifying jurisdictions, including the United States. The common shares offered under the listed issuer financing exemption will be immediately free-trading upon closing of the offering under applicable Canadian securities laws.

There is an amended and restated offering document related to this offering that can be accessed under the company's profile at SEDAR+ and at the company's website. Prospective investors should read this amended and restated offering document before making an investment decision.

The closing of the offering is expected to occur on or about Oct. 14, 2026, or on such date as the agents and the company may agree upon. Closing is subject to the company receiving all necessary regulatory approvals, including the conditional approval of the Canadian Securities Exchange.

The agents will receive a cash commission of 6.0 per cent of the aggregate gross proceeds of the offering, up to $6.9-million in gross proceeds, such cash commission reduced to 1.0 per cent for gross proceeds exceeding such amount, and such number of broker warrants as is equal to 6.0 per cent of the number of common shares sold under the offering, up to $6.9-million in gross proceeds (in each case, subject to reduction to 3.0 per cent for certain subscribers on a president's list of purchasers identified by the company). Each broker warrant entitles the holder to purchase one common share at an exercise price equal to the issue price for a period of 24 months following the closing.

Technical disclosure

Qualified persons: Joled Nur, registered member of the Comision Calificadora de Competencias en Recursos y Reservas Mineras, registration No. 181, of SRK, is the independent qualified person for the inferred resource, as defined by National Instrument 43-101.

Francisco Bravo, a resident of Santiago, Chile, and the company's chief geologist, is a qualified person as defined by National Instrument 43-101, and has reviewed and approved the scientific and technical information in this news release. Mr. Bravo is not independent of the company within the meaning of NI 43-101. Mr. Bravo is registered with the Comision Calificadora de Competencias en Recursos y Reservas Mineras, Registro No. 51, and is registered with the Colegio de Geologos de Chile (No. 725).

Inferred mineral resources: The resource estimate is classified entirely in the inferred category. Mineral resources that are not mineral reserves do not have demonstrated economic viability. Inferred mineral resources are subject to a high degree of uncertainty, and there is no assurance that any part of an inferred mineral resource will be converted to an indicated or measured mineral resource or to a mineral reserve.

About Aterra Metals Inc.

Aterra Metals is a mineral exploration company advancing copper-gold projects in Chile. The company's flagship Totora copper-gold project is located in the Dos Amigos mining district of Region III, Chile, approximately 60 kilometres south of Vallenar. The project comprises the Taruca, Clinton, Frontera and Sevilla properties, and hosts the Frontera, Totora, Algarrobilla and Clinton copper-gold porphyry systems, together with earlier-stage exploration targets. The company holds its interests in the project under option agreements.

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