The Federal Housing Finance Agency is toying with the idea of “grandfathering” current captive insurance affiliates in the Federal Home Loan Bank system, while blocking out others, according to industry observers tracking the matter.If the FHFA does so, it would benefit mortgage-backed security investing real estate investment trusts that gained entry through a captive. A few years back, REITs found a loophole in the FHLB membership rules and exploited it before the FHFA put a moratorium on captives joining the system and requested industry comments on the captive angle and other membership rules. The moratorium expired in early 2015 and the 11 regional FHLBs once again began allowing REITs and others – via their captives – to join the system.