Illinois Tool Works Inc., a sprawling combine of nearly 800 business units in numerous industries from food services to auto parts, routinely acquires dozens of small companies each year. It did not respond to a request for comment for this story, but has told the Wall Street Journal it has no plans to divest any major businesses.

In short, the lesson from the current trend towards de-conglomerating is that it may just be a wrinkle in the fabric of business judgments CFOs, investors and others are constantly making, says Steven M. Davidoff, a law professor at the University of Connecticut who is the "Deal Professor" at the New York Times's DealBook weblog.

"Just spinning off a business does not create value," says Davidoff. For example, "spin-offs are a very easy way for management to get rid of businesses they may not like as much. Bad spin-offs are subsumed within the good ones."