Investors, servicers, sponsors and other professionals involved in securitizing real estate debt are pinching themselves over the success their industry has enjoyed the past couple of years. But everybody knows the good times will not roll on forever. What's keeping investors up at night is figuring out when the other shoe is going to drop. That was the buzz at January's Commercial Mortgage Securities Association CMBS Investors Conference held in Miami.

With everything humming along, spreads between the tiered credit rankings have tightened. That poses a risk. The lack of any downturns in CMBS means that fewer people in the industry have experience working through a down cycle.

“We don't have a lot of skilled people with experience to deal with workouts,” said Charles Spetka, president of CW Capital Asset Management. When things do go bad, experts expect there will be a race to hire anyone with experience navigating choppy waters.

Of all the property types, CMBS investors are the most bearish on the retail sector. Randy Mundt, president and chief investment officer for Principal Real Estate Investors, cited the lack of optimism for the retail sector, which prompted this exchange.

“We're most cautious on retail today,” Mundt said. “We're concerned by consumer-related issues and worried about retailer credit. … And now, there's a lot of LBO activity, which is worrisome.”

Michael Gilberto, managing director for JP Morgan Asset Management, added that he wasn't too optimistic about shopping centers because of the amount of construction in that sector. “Those centers have built more space than any time since 1990,” he said.