Billionaire Bill Ackman postpones IPO for Pershing Square USA New York Post Bill Ackman’s IPO of Pershing Square closed-end fund is postponed, NYSE says CNBCBill Ackman postpones Pershing Square IPO after scaling back expectations Financial TimesBill Ackman’s own hedge fund is asking investors to ignore what he says FortuneAckman Eyes $4 Billion for Closed-End Fund, Short of Goal Bloomberg