** FILE ** Billionaire real estate investor Sam Zell ponders a question during an interview in this March 20, 2007, file photo. Tribune Co. shareholders were poised to sign off Tuesday, Aug. 21, 2007 on the $8.2 billion buyout of the media conglomerate, although questions remain about whether the deal led by billionaire Sam Zell will go through as currently structured. (AP Photo/M. Spencer Green, file)