Calgary, Alberta--(Newsfile Corp. - May 13, 2026) - Rain City Resources Inc. (CSE: RAIN) - Rain City Resources Inc. ("Rain" or the "Company") is pleased to announce that it has entered into a strategic collaboration with Fundación Fraunhofer Chile Research, part of the broader Fraunhofer network, one of the world's most respected applied research platforms and a recognized benchmark in industrial innovation, engineering, and technology validation.

The agreement materially strengthens Rain's technical, metallurgical and commercial platform across the Lithium Triangle, with particular focus on Argentina, Bolivia and Chile, and supports the advancement of the Company's next-generation Direct Lithium Extraction ("DLE") technology designed for very low or near-zero water consumption, improved process efficiency and broader deployment across complex brine environments.

Under the Memorandum of Agreement ("MoA"), Rain and Fraunhofer Chile will establish a framework for collaboration in technology validation, process optimization, pilot development, renewable energy integration, circular economy solutions, sustainability assessment, and broader project execution related to advanced lithium extraction and processing. The collaboration is intended to support Rain's DLE platform across diverse brine chemistries and operating conditions, while reinforcing and elevating the technical, institutional and commercial relationships the Company has already been advancing in the region.

For Rain, the significance of this alliance extends beyond institutional visibility. Fraunhofer's applied research model, engineering depth and international industrial network are expected to strengthen technical de-risking, metallurgical validation, pilot-stage preparation and commercialization pathways. The MoA also provides for project-specific agreements, feasibility studies, technical exchanges, coordinated oversight and international funding initiatives tied to future collaborative programs.

The agreement further contemplates multi-jurisdictional feasibility studies, pilot installations, prototype testing and commercial demonstration projects in the Lithium Triangle, together with an International Joint Steering Committee to oversee implementation, strategic alignment and disciplined execution. The parties have also committed to move toward binding project agreements and concrete collaborative programs within a defined post-signing implementation period.

Benjamin Hill, CEO of Rain, commented, "Fraunhofer Chile brings a globally respected applied research and engineering platform to Rain at an important stage in the advancement of our next-generation DLE technology. This alliance strengthens our ability to validate performance, advance pilot readiness and execute with greater technical depth across the Lithium Triangle."

Sebastian Quiñones, Head of Rain LATAM and Board Advisor of Rain, stated, "This is a strategically important alliance from a technical, metallurgical and commercial standpoint, particularly in a region where brine complexity, operating conditions and regulatory frameworks vary significantly. It not only supports the advancement of our new DLE platform with Ion Source but also deepens the partnerships already in motion and strengthens Rain's position in Argentina, Bolivia and Chile."

Rain believes this collaboration can contribute meaningfully to the advancement of more efficient, scalable and sustainable lithium development in South America, while strengthening the Company's engagement with producers, institutions, strategic counterparties and downstream participants across the battery materials value chain.

About Rain City Resources Inc.

Rain City Resources Inc. is a Canadian public company focused on advancing next-generation Direct Lithium Extraction technologies and building strategic development pathways across the Lithium Triangle and other high-potential jurisdictions. The Company is committed to supporting more efficient, scalable and sustainable lithium production through technical innovation, disciplined execution and regional partnerships.

About Fundación Fraunhofer Chile Research

Fundación Fraunhofer Chile Research is part of the broader Fraunhofer network, one of the world's leading applied research organizations and a recognized benchmark in industrial innovation, engineering and technology transfer. Through applied, industry-oriented research, Fraunhofer supports the development and commercialization of advanced technologies across strategic sectors, including energy, materials, sustainability and industrial processes.

FOR FURTHER INFORMATION CONTACT:

Cautionary Note Regarding Forward-Looking Information

This news release contains forward-looking statements and forward-looking information within the meaning of applicable Canadian securities laws (collectively, "forward-looking statements"). Forward-looking statements relate to future events or future performance and reflect management's current expectations, beliefs and assumptions. Generally, forward-looking statements can be identified by the use of terminology such as "expects", "anticipates", "plans", "intends", "believes", "may", "could", "should", "would" or similar expressions.

Forward-looking statements in this release include, without limitation, statements regarding: the expected benefits of the collaboration with Fundación Fraunhofer Chile Research; the advancement, validation and commercialization of Rain City's direct lithium extraction ("DLE") technology; pilot development and metallurgical optimization initiatives; renewable energy integration; commercial demonstration projects; potential project-specific agreements and funding opportunities; the Company's strategic positioning and expansion opportunities in Argentina, Bolivia and Chile; the Company's proposed financing plans; and management's expectations regarding future operations, business development initiatives and strategic plans.

Forward-looking statements are based on a number of assumptions believed by management to be reasonable at the time such statements are made, including assumptions regarding the ability of the parties to advance collaborative initiatives, the availability of financing, favorable market conditions, and the successful execution of the Company's business plans. However, forward-looking statements are subject to known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements to differ materially from those expressed or implied herein. Such risks and uncertainties include, without limitation: the inability to execute business plans as intended; delays or challenges in technology development, validation or commercialization; the inability to secure adequate financing or strategic partnerships; changes in commodity prices, market demand or regulatory frameworks; general economic, financial and market conditions; geopolitical and operational risks associated with international operations; and volatility in the financial markets for the Company's securities.

Although management has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking statements, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that forward-looking statements will prove to be accurate, as actual results and future events could differ materially from those anticipated. Accordingly, readers should not place undue reliance on forward-looking statements. The Company undertakes no obligation to update or revise any forward-looking statements or financial outlooks, except as required by applicable securities laws.

Neither the Canadian Securities Exchange nor its Regulation Service Provider (as such term is defined in the policies of the Canadian Securities Exchange) accepts responsibility for the adequacy or accuracy of this news release.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/297317