Billionaire hedge fund manager Bill Ackman is one of the most powerful figures on Wall Street. After serving the world's wealthiest investors for decades, he is planning to take his firms public and the Pershing Square Capital Management founder and CEO didn't take long to kick off the roadshow. Related: 'Big Short' Michael Burry backs billionaire Bill Ackman's Fannie and Freddie 10x call On Apr. 13, Ackman announced a combined initial public offering (IPO) of two companies: Pershing Square USA, Ltd. ...