This is a sources sought notice for market research, not a solicitation, supporting the Department of the Interior's Construction Multiple Award Contract (C-MAC) for Indian Affairs, which is set aside for Indian Small Business Economic Enterprises (ISBEEs). The C-MAC covers design-build and design-bid-build construction projects across the Continental U.S. and Indian Country, including new construction, renovation, and infrastructure work. The total combined contract value is capped at $1.5 billion over a five-year ordering period ending in May 2028, with typical individual projects ranging from $5 million to $60 million, while stand-alone contracts may range from $500,000 to $200 million or more. The government plans to begin re-procurement planning in fiscal year 2027 and is currently gathering contractor qualifications for potential future on-ramping. Interested ISBEEs should respond with company information, past project experience, and a description of how they will meet subcontracting limitations.