Bond buyers are devouring the most commercial-mortgage debt linked to everything from skyscrapers to Hawaiian resorts in more than five years, allaying concern that an onslaught of sales would be too much to digest.

Even as Bank of America Corp. estimates sales of the securities more than doubled to $10.7 billion this month, investors have pushed down the rate on the top-ranked portion of transactions maturing in 10 years to 0.72 percentage point above the benchmark swap rate of 2.06 percent. That difference is the narrowest since issuance revived in 2009.