Imposes an excise tax on certain hedge funds failing to dispose of excess single-family residences, escalating over a ten-year period. Imposes a tax on any newly acquired single-family residences by a hedge fund. Makes certain exemptions. Requires the Department of Taxation to establish a certification process to ensure buyers of homes sold by hedge funds are not major investors in residential real estate. Establishes the Housing Down Payment Trust Fund to be administered by the Hawaii Housing Finance and Development Corporation to provide grants to establish new or supplement existing programs that provide down payment assistance to families purchasing homes within the State. Allocates collected tax revenue and penalties paid by hedge funds to the Housing Down Payment Trust Fund. Applies to taxable years beginning after 12/31/2025.