Lithium Americas to Join the S&P/TSX Composite Index

(All amounts in US$ unless otherwise indicated)

Lithium Americas Corp. (TSX: LAC) (NYSE: LAC) ("Lithium Americas" or the "Company") announced that, as disclosed by S&P Dow Jones Indices on December 5, 2025, the Company's common shares will be added to the S&P/TSX Composite Index, effective prior to the open of trading on Monday, December 22, 2025. The S&P/TSX Composite Index is Canada's premier equity benchmark and includes the largest and most actively traded companies on the Toronto Stock Exchange.

Jonathan Evans, President and CEO said, "Our inclusion on the S&P/TSX Composite Index demonstrates the significant progress Lithium Americas has made as we advance Thacker Pass toward production to onshore industrial-scale lithium production by late-2027. This milestone highlights our commitment to creating long-term value for our stakeholders and underscores our position in the North American critical mineral supply chain."

ABOUT LITHIUM AMERICAS

Lithium Americas is building Thacker Pass located in Humboldt County in northern Nevada ("Thacker Pass"). Phase 1 of Thacker Pass is designed for nominal production capacity of 40,000 tonnes per year of battery-quality lithium carbonate, and mechanical completion is targeted for late-2027. Thacker Pass hosts the largest known measured lithium resource (Measured and Indicated) and reserve (Proven and Probable) in the world and is owned by a joint venture between Lithium Americas (holding a 62% interest), and General Motors Holdings LLC ("GM") (holding a 38% interest). Project financing for Phase 1 of Thacker Pass includes a $2.23 billion loan from the U.S. Department of Energy (the "DOE Loan") and strategic investments from GM and Orion Resource Partners LP. Construction of Phase 1 of Thacker Pass is expected to create nearly 2,000 direct jobs, including 1,800 skilled contractors. Lithium Americas' shares are listed on the Toronto Stock Exchange and New York Stock Exchange under the symbol LAC. To learn more, visit www.lithiumamericas.com or follow @LithiumAmericas on social media.

FORWARD-LOOKING STATEMENTS

This news release contains "forward-looking information" within the meaning of applicable Canadian securities legislation, and "forward-looking statements" within the meaning of the Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended (collectively referred to as "FLS") and is subject to important risks and uncertainties (such statements are usually accompanied by words such as "anticipate," "plan," "continues," "estimate," "expect," "may," "will," "projects," "predict," "proposes," "potential," "target," "implement," "scheduled," "forecast," "intend," "would," "could," "might," "should," "believe" and similar terminology, or statements that certain actions, events or results "may," "could," "would," "might" or "will" be taken, occur or be achieved). FLS in this news release include, but are not limited to: statements relating to project financing for Phase 1 of Thacker Pass, including the DOE Loan and strategic investments; estimates of, and changes to, mineral resources and mineral reserves at Thacker Pass, their development and realization; the Company's ability to produce high-purity, battery-grade lithium products; the timing, quantity, capacity and product quality of future production at Thacker Pass; successful development of Thacker Pass; and anticipated job creation.

FLS statements in this news release are intended to provide Lithium Americas security holders and potential investors with information regarding the Company, including management's assessment of Lithium Americas and its subsidiaries' future plans and financial outlook. All forward-looking statements reflect the Company's beliefs and assumptions based on information available at the time the statements were made and as such are not guarantees of future performance. Such statements are subject to a number of assumptions, risks and uncertainties, many of which are beyond the Company's control. Additional information about these assumptions and risks and uncertainties is contained in the Company's filings with securities regulators, including the Company's most recent Annual Report on Form 10-K and in any subsequently filed Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, and other disclosures in each case made available on SEDAR+ at www.sedarplus.ca and on EDGAR at www.sec.gov. As actual results could vary significantly from the forward-looking information, you should not put undue reliance on forward-looking information and should not use future-oriented information or financial outlooks for anything other than their intended purpose.

The FLS contained in this news release is expressly qualified by these cautionary statements. All FLS in this news release speaks as of the date hereof. The Company does not undertake any obligation to update or revise any FLS, whether as a result of new information, future events or otherwise, except as required by law.

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INVESTOR CONTACT
Virginia Morgan, VP, IR and ESG
+1-778-726-4070
ir@lithiumamericas.com