While the worst of the commercial real estate downturn may be in the rearview mirror, industry analysts say cleaning up the mess left behind won't be easy. "We may be seeing the peak of the cycle," said Greg Leisch, chief executive of the Delta Associates real estate research firm. "For the first time in the cycle, we've seen a decline in construction loan delinquencies. "And commercial mortgage-backed securities delinquencies have stopped their upward spiral as well," he said. "We've got a rebound in property values, only after two years of a downturn in values."