Landlords are paying off more boom-era loans early, chipping away at $316 billion of debt maturing through 2017 that has loomed over the commercial-mortgage backed securities market since the credit seizure six years ago.

Owners of U.S. properties from skyscrapers to hotels have extinguished $17 billion of debt before it was due during the past 12 months, more than four times the amount retired before maturity in 2011 and 2012 combined, according to Credit Suisse Group AG. Proprietors of the Mall of America, the largest shopping center in the U.S., are getting a $1.4 billion loan to repay borrowings that don’t mature until 2016.