Bill Ackman is a self-described ‘Buffett devotee’—and wants his $28 billion Pershing empire to be the ‘modern-day’ Berkshire

Bill Ackman has never been one to temper his ambitions, but by filing to take Pershing Square public, he may have taken the first step toward reaching his biggest goal yet—to create his own “modern-day” Berkshire Hathaway by following in the footsteps of one of the world’s most successful investors, Warren Buffett.

Pershing Square Capital Management on Tuesday filed to be listed on the New York Stock Exchange, marking Ackman’s second attempt to take the company public after an ambitious...