Several of the biggest corporate buyouts in recent years are in trouble, says Breakingviews.com, especially Sam Zell's highly leveraged take over of Tribune.

Tribune looks to be the megadeal most at risk, the publication notes. Sam Zell’s $12 billion buyout of the company, the publisher of The Los Angeles Times and The Chicago Tribune, was financed nearly entirely with debt. Operating cash flow was down by 66 percent in the third quarter. Tribune is on the cusp of breaching its debt covenants, and some of its bonds trade for as little as 9 cents on the dollar. With the advertising market deteriorating in line with the economy, Tribune has few easy options to stabilize its revenue.

Clear Channel, the radio broadcaster, is also "deteriorating fast." Via New York Times