(Reuters) -Billionaire investor Bill Ackman's Pershing Square Capital Management said on Tuesday it would buy 10 million newly issued shares of Howard Hughes Holdings ( HHH ) for $90 apiece in its revised proposal for the real estate developer.

Shares of Howard Hughes dipped 4.2% after the bell.

The proposed deal would take Pershing's stake in Howard Hughes to 48% from 37.6%.

Under the proposal, Ackman would become chairman and CEO of Howard Hughes, Pershing said.