Billionaire hedge fund manager Bill Ackman postponed the highly-publicized public offering for Pershing Square USA, according to a notice on the New York Stock Exchange’s website on Friday.

The deal had been slated to price on Monday and trade the following day, according to terms of the deal seen earlier by Bloomberg News reported.

The delay comes a day after Ackman slashed the fundraising target for the US fund from $25 billion to between $2.5 billion to $4 billion.

Even that lower target could prove difficult.

“Bill could not raise more than the $1 billion he got from friends,” a source directly involved in the IPO told The Post on Friday.

“People want to see where it trades first before investing.”

Ackman didn’t return The Post’s request for comment.

Pershing Square issued a press release after the news broke, insisting that the IPO will proceed “with the date of pricing to be announced.”

The IPO could go live sometime in the next two weeks with common shares priced at $50, the release added.

On Thursday, Ackman filed an update with the SEC that included a letter Ackman penned to shareholders in his Pershing Square Capital Management firm asking them to back the new investment venture.

The Harvard graduate – who has become a fixture on social media with posts about the rampant antisemitism on college campuses – told shareholders they should get involved in the IPO “the sooner the better” to “improve the strength” of the deal.

“He doesn’t want a subscale listing,” the source said, “99% of companies like this trade at a discount to net asset value and he thought because of his public persona he would buck the trend but he didn’t.”

Ackman’s fund has returned 16.5% a year.  

The 58-year-old  – who has a net worth of $9.1 billion, according to Forbes and endorsed former President Donald Trump soon after he was shot – recently sold a stake in the firm that valued it at more than $10 billion.

With James Franey