Why: Ackman has for months been pursuing Howard Hughes in a bid to create the next Berkshire Hathaway.Berkshire Hathaway was a textile company when Warren Buffett acquired it in 1965. The legendary investor and his partner Charlie Munger merged two other companies — Diversified Retailing and Blue Chip Stamps — with Berkshire in 1978 and 1983 before closing the textile firm's failing business in 1985.

A key problem is that the Howard Hughes board and the special committee evaluating the proposal may not want to turn the company into an Ackman-led mini Berkshire.