The 8(a) Small Business Integrity and Stability Act of 2026 directs the Small Business Administration to extend and reinstate participation in the federal 8(a) program, which provides contracting assistance to small disadvantaged businesses. The bill allows currently participating 8(a) businesses to receive a one-year extension of their program participation, and permits businesses whose participation was terminated for failing to respond to information requests or who voluntarily withdrew between January 2026 and October 2026 to be reinstated and also extend their participation for an additional year. The Small Business Administration must issue implementing rules within 15 days of the bill's enactment, with a firm deadline of 75 days to complete the rulemaking process. The legislation also preserves the eligibility standards for social disadvantage that were in place as of June 11, 2026, protecting businesses that were already determined to qualify under those rules. This bill primarily affects small business owners participating in or recently separated from the 8(a) program and does not specify new funding amounts.