The few real estate investment trusts that currently have access to advances from the Federal Home Loan Banks would lose their ability to tap the attractive funding source under a proposal last week from the Federal Housing Finance Agency. The FHFA said the proposed rule is necessary because REITs with captive insurance companies pose risks to the FHLBank system. “FHFA is taking these actions to address supervisory concerns about certain institutions that are ineligible for FHLBank membership, but that are using captive insurers as vehicles through which they can obtain FHLBank advances to fund their business operations,” the federal regulator said.