What is the real-estate term for a loan secured by several properties under one mortgage?

A loan secured by several properties under one mortgage is called a blanket mortgage.

A blanket mortgage covers multiple parcels or properties as collateral for one loan. Real-estate investors and developers may use this structure to finance a portfolio, a subdivision, or several buildings without arranging a completely separate mortgage for every property.

Many blanket mortgages include a release clause. That clause allows a borrower to release one property from the mortgage after paying an agreed amount, which can make it possible to sell individual lots or buildings while keeping the remaining properties financed. Terms vary widely, so the release price and collateral rules are important parts of the agreement.

A blanket mortgage is not simply any large commercial mortgage. A loan on one large building is generally secured by one property, even if its balance is substantial. It is also different from a bridge loan, whose defining feature is temporary financing intended to bridge a gap between transactions or longer-term funding.