As borrowing costs plunge for the highest-quality companies,there's a growing incentive for riskier businesses like fast-foodchains to mortgage virtually all their assets.

Franchised companies like burger restaurant Jack in the Box Inc.and massage provider Massage Envy are increasingly selling unusualbonds backed by most of their business. By pledging key assets likeroyalties, fees, and intellectual property to bondholders,companies can win investment-grade credit ratings on their debt andslash their financing costs, making their bonds higher quality evenif their overall companies are still relatively risky.

This year borrowers have sold more than $6.9 billion of thesesecurities, known as whole-business securitizations, approachingthe most on record, according to data compiled by Bloomberg.Fast-food restaurants used to be the main issuers of this debt, buta wider array of companies are now jumping in. This year, inaddition to Massage Envy, a group of preschools and a distributorof music royalties have sold the bonds.