entities in connection with the sale of single family real properties owned by the Secretary and formerly insured under such Act. Government national mortgage association Guarantees of mortgage-backed securities loan guarantee program account New commitments to issue guarantees to carry out the purposes of section 306(g) of the National Housing Act, as amended ( 12 U.S.C. 1721(g) ), shall not exceed $1,500,000,000,000 in aggregate principal, to remain available until September 30, 2022: Provided , That $55,500,000, to remain available until September 30, 2022, shall be for necessary salaries and expenses of the Office of Government National Mortgage Association: Provided further , That to the extent that guaranteed loan commitments exceed $155,000,000,000 on or before April 1, 2021, an additional $100 for necessary salaries and expenses shall be available until expended for each $1,000,000 in additional guaranteed loan commitments (including a pro rata amount for any amount below $1,000,000), but in no case shall funds made available by this proviso exceed $3,000,000: Provided further , That receipts from Commitment and Multiclass fees collected pursuant to title III of the National Housing Act ( 12 U.S.C. 1716 et seq.) shall be credited as offsetting collections to this account. Policy development and research Research and technology For contracts, grants, and necessary expenses of programs of research and studies relating to housing and urban problems, not otherwise provided for, as authorized by title V of the Housing and Urban Development Act of 1970 ( 12 U.S.C. 1701z-1 et seq.), including carrying out the functions of the Secretary of Housing and Urban Development under section 1(a)(1)(i) of Reorganization Plan No. 2 of 1968, and for technical assistance, $118,000,000, to remain available until September 30, 2022: Provided , That with respect to amounts made available under this heading, notwithstanding section 203 of this title, the Secretary may enter into cooperative agreements with philanthropic