; or (III) the limitation in effect for such size residence for such area, pursuant to the last sentence of this paragraph as in effect immediately before the enactment of the Protecting American Taxpayers and Homeowners Act of 2018, as of the date of such enactment. (ii) Prohibition on new high-cost areas The limitations established pursuant to subparagraph (A) may not be increased, with respect to properties of any size located in a particular area unless, as of the date of the enactment of the Protecting American Taxpayers and Homeowners Act of 2018, such foregoing limitations in effect for such area for any size residence were determined under the authority provided in the last sentence of this paragraph, as in effect immediately before such enactment. . 105. Mandatory risk-sharing Subpart A of part 2 of subtitle A of the Federal Housing Enterprises Financial Safety and Soundness Act of 1992 is amended by adding after section 1327 ( 12 U.S.C. 4547 ) the following new section: 1328. Mandatory risk-sharing transactions (a) In general The Director shall require each enterprise to develop and undertake transactions involving the guarantee by the enterprises of securities and obligations based on or backed by mortgages on residential real properties designed principally for occupancy of from 1 to 4 families that provide for private market participants to share or assume credit risk associated with such mortgages, as follows: (1) Required percentage of business The Director shall require that not less than 10 percent of the annual business of each enterprise (as measured in such manner as the Director shall determine) in guaranteeing such securities and obligations involve such transactions. (2) Multiple types of transactions The Director shall require that in complying with paragraph (1), each enterprise undertake multiple types of the various transactions and structures described in subsection (b). (b) Types of transactions The risk-sharing transactions referred to in subsection (a) may include transactions