S. 4915 is a bill that addresses two main areas: affordable housing and international trade preferences. On housing, the bill increases the amount of federal tax credits available to states for building and rehabilitating low-income housing in calendar years 2023, 2024, and 2025. It also modifies rules about how much of a low-income housing project must be financed with tax-exempt bonds to qualify for these credits, providing more flexibility for developers. On trade, the bill extends and reforms the Generalized System of Preferences, a program that gives certain developing countries duty-free access to U.S. markets, by extending it through December 2029 and adding new eligibility requirements related to environmental protection, human rights, worker rights, and anti-corruption efforts. The bill also requires the U.S. Trade Representative to conduct regular reviews of participating countries' compliance with these standards and report findings to Congress, with a comprehensive study due by July 2026. The housing provisions take effect for buildings placed in service after December 31, 2023, while the trade provisions become effective 30 days after enactment.