Billionaire investor Bill Ackman has called the slumping stock price of his publicly traded investment fund, Pershing Square USA, "frankly absurd." The fund, along with Ackman's firm, went public in April, but its performance since then has lagged behind the broader market.

Pershing Square USA's stock has experienced a decline since its initial public offering. Ackman, a prominent figure in the investment world, has expressed his dissatisfaction with the fund's recent performance, particularly in comparison to market benchmarks. The fund's public listing was intended to provide greater liquidity and transparency, but the market's valuation of the company has not met expectations.

Further details on the specific metrics causing Ackman's concern and the fund's investment strategy were not immediately available, but the investor's public commentary highlights a disconnect between his perception of the fund's value and its current market trading price.