Investors are breathing life back into a once-dead financing tool. The market for bundled loans used to fund riskier real-estate projects is on pace for a post-crisis record after all but disappearing during the 2008 crash.

Sales of commercial real estate collateralized loan obligations are expected to double from last year to as high as $20 billion this year, which would be the highest since 2007, according to industry analysts.

The renaissance of the so-called CRE CLOs — which are used to fund properties that don't qualify for traditional financing, such as suburban office complexes, multi-family housing and malls that are in transition — is being hotly debated. Some investors like the better returns and protection from rising interest rates from the floating-rate securities, while others warn of the higher risk of defaults and looser underwriting standards.