Kenneth Laub has been through three commercial real estate boom and bust cycles during almost five decades as a broker and consultant to corporations such as Hess Corp. and International Paper Co. He says the current downturn will overshadow all of the others, Bloomberg Markets reports in its February 2010 issue. “It won’t be a typical part of a cycle where we’re down for two or three years and things recover,” says Laub, 70, whose New York firm, Kenneth D. Laub & Co., says it has handled more than $40 billion of real estate transactions since its inception in 1969. “It will be longer than we’ve gone through before.”