Nearly a decade ago, some investors scored big payouts by predicting that the housing boom’s glut of mortgage-backed securities would turn out to be toxic. Now there are investors betting on the hope that more mall owners will soon be letting their properties go into foreclosure.

The question for the firms betting against malls is how long it will take for that to happen. Anchors like Macy’s, JCPenney, and Sears are helping some malls along by accelerating their closings across the country in the hope of staying in business and finding a functional business model.

For malls that are able to keep enough rent coming in to survive, though, the demise of their department stores may not kill them off in the way that some investors predict. Shoppers are no longer all that interested in shopping at department stores anyway, and as traditional anchors close, non-traditional ones like supermarkets, party spaces, and fast fashion clothing stores are taking their place.

What investors are realizing, though, is that when a mall fails, it is a multimillion-dollar failure. Bloomberg reports that investors interested in betting against malls pay premiums every year that will pay off in the event that enough malls fail and the value of the mortgage-backed securities plummets.

Prices are starting to fall, but the malls haven’t failed yet. Still, the investors making these bets are patient.

“These malls are dying, and we see very limited prospect of a turnaround in performance,” a report at the beginning of the year from Alder Hill, one firm shorting mall-backed securities, informed investors. “We expect 2017 to be a tipping point.” More failures may come after all of those anchors close.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.