Bill Ackman’s hedge fund Pershing Square – known for its contrarian bets – is expected to raise $5 billion in its IPO, at the bottom of its targeted range, a source familiar with the matter told The Post.The billionaire investor earlier said he was looking to raise between $5 billion and $10 billion in a dual-IPO of his closed-end fund and hedge fund, which will each trade on the New York Stock Exchange under the name Pershing Square – with ticker symbols PSUS and PS, respectively.But the final offer size w ...