This bill establishes new excise taxes and regulations to curb the ownership of single-family residences by hedge funds and other large institutional investors. It imposes a significant 50 percent excise tax on the fair market value of any newly acquired single-family residence by an "applicable taxpayer" after the bill's enactment. An "applicable taxpayer" is defined as a person managing pooled funds from investors and acting as a fiduciary, with exceptions for organizations primarily engaged in construction or rehabilitation. Furthermore, the bill introduces an annual excise tax of $50,000 per residence for "applicable taxpayers" who fail to meet specific disposition requirements for their existing single-family residences. For "hedge fund taxpayers," defined as those with $50 million or more in net value or assets under management, the bill mandates a phased reduction of their single-family residence holdings to zero over nine years. Other applicable taxpayers are allowed to retain up to 50 residences plus a declining percentage of their initial holdings over the same period. Sales to other businesses or individuals already owning another single-family residence are deemed "disqualified sales" and do not count towards reducing the taxpayer's inventory for tax purposes. To further discourage large-scale ownership, the legislation disallows mortgage interest and depreciation deductions for single-family residences owned by taxpayers subject to the excess residence tax. It also prohibits federal mortgage entities like Fannie Mae, Freddie Mac, and Ginnie Mae from purchasing, securitizing, or guaranteeing mortgages where the mortgagee is a "specified large investor." All revenues generated from these new excise taxes will be directed into a newly created Housing Downpayment Trust Fund . This trust fund will finance grants to State housing finance agencies, enabling them to provide down payment assistance, closing cost support, and interest rate buydowns for individuals and families earning up to 120 percent of the area median income. Priority for this assistance will be given to those purchasing homes sold by the targeted applicable taxpayers. The bill also mandates comprehensive reporting requirements for applicable taxpayers regarding their acquisitions and sales, with penalties for non-compliance, and requires purchasers to certify they do not own other single-family residences.