Bill Ackman is a billionaire hedge fund manager. NYSE Bill Ackman announced a new investment in Microsoft. The billionaire investor said both his hedge fund and new closed-end fund had taken positions. Ackman touted Microsoft's ownership of M365 and Azure and the recent slump in its stock price. Bill Ackman is betting big on Microsoft's success in the AI era. Billionaire investor Ackman said on Friday that his hedge fund, Pershing Square Capital Management, has taken a position in Microsoft, saying he has been following the company for many years and that it now has a "highly compelling valuation." Ackman introduced the Microsoft stake in an X post, saying his team has "found occasional opportunities to acquire some of the most dominant long-term compounding franchises at attractive valuations." He gave Alphabet , Amazon, and Meta as examples in recent years.…