US SB3904

Denies interest and depreciation deductions for residential rental properties where institutional investment entities hold a majority interest, or single-family properties where "large owners" (those holding 50+ dwelling units) have majority interest

Exempts from these restrictions: sales to individuals for primary residences, sales to qualified nonprofits focused on affordable housing, newly constructed housing (5-year exemption for single-family, permanent for multi-family), substantial rehabilitation of uninhabitable properties, and federally assisted or low-income tax credit housing

Prohibits federal agencies (HUD, VA, USDA, Fannie Mae, Freddie Mac) from selling foreclosed homes or federally backed mortgage loans to large owners or institutional investment entities, and bars them from issuing new mortgage financing to such investors

Allocates estimated tax savings: 80% to HUD for HOME Investment Partnerships affordable housing funding, and 20% to establish a down payment assistance fund (up to $20,000 or 10% of purchase price) for first-time, first-generation homebuyers earning up to 120-140% of area median income

Amends Clayton Act to require antitrust reporting for aggregated residential property acquisitions, establishes presumption that acquisitions increasing market share above 30% violate antitrust laws