Older, low-end malls are worth at least 50% and in some cases more than 70% less than they were when mall valuations peaked in late 2016, said Vince Tibone, head of U.S. retail and industrial research for real-estate research firm Green Street, the Wall Street Journal reported. Now, as more than $14 billion of loans backed by these properties comes due in the next 12 months, according to Moody’s Analytics, struggling malls are defaulting on their debt. With mortgage rates up sharply, refinancing that debt will be more challenging and expensive. About a fifth of all malls financed through commercial mortgage-backed securities are underwater, meaning the properties are worth less than the loans they back, said Kevin Fagan, head of commercial real-estate economic analysis for Moody’s.