With more than $9B in outstanding CMBS loans due for repayment in June, research firm Morningstar says the rate at which they’re being paid off increased by 2.7% last month.

Most of the matured loans fell within the retail, office, hotel and industrial sectors, accounting for more than 80% in unpaid balances combined. Last month, 479 matured loans were paid in full, totaling $6.14B, and dropping the payoff rate to 78.5% from 85.1% in May.

Though Morningstar projects the payback rate will continue to fall as the year progresses, the research suggests loans taken out between 2006 and 2007 may be unable to be refinanced.

Morningstar CMBS VP Edward Dittmer tells Bisnow the firm is forecasting a refinance rate of about 60%, which would mean that 40% of the loans will not pay off on time.

Of the near 480 loans paid last month, 18.7% were delinquent—two of which had balances of more than $100M. Morningstar’s future 2017 outlook shows $100B of CMBS loans will mature in 2017, and most will not have the option to refinance.

“In terms of the CMBS issuance outlook for 2017, the big unknown is how the risk retention rules set to take effect this Christmas Eve will be satisfied and the effect the likely increased cost of funding will have on the ability of CMBS lenders to compete with other CRE lenders,” Morningstar CMBS head Kenneth Cheng tells Bisnow.

New financial oversight regulations are set to take effect this year requiring CMBS loans to retain a 5% chunk of each CMBS deal for five years. The rules—which take effect Dec. 24—have caused some concerns for CMBS lenders already reeling from a year-to-date 50% decline in overall insurance last year, CoStar reports.

“The CMBS market is just now starting to recover from the disruption caused by the volatile credit market earlier this year and any momentum built up over the next few months could be interrupted by these risk retention rules,” Kenneth says.