Of the $61.1B in commercial mortgage-backed security debt set to mature within the next six months, $6.7B is due in March.

Most of these loans were issued in the late stages of the commercial real estate bubble, either in 2006 or 2007, and with the current tightening of banks it is unclear whether many of these properties will meet today’s credit standards.

Office loans make up 28.9% of the debt while retail loans account for 26.5%, according to the latest Trepp report.

More than 9.7% of the CMBS debt to mature in March is in default and 14.2% has been transferred to special servicing. A $1.1B loan for 5 Times Square in Midtown Manhattan is the largest CMBS loan set to mature this month, and tenant Ernst & Young rents most of the building under a lease that ends in 2022.

Many experts are worried that retail closures could seriously hurt the economy should these companies fail to make their loan payments. Adding to that fear, JC Penney recently announced store closings that put almost $7B of CMBS loans in jeopardy.