Bill Ackman and David Tepper aren't exactly two peas in a pod. They have quite different investing styles. However, the two men nonetheless share several things in common. Both started hedge funds -- Ackman with Pershing Square Capital Management and Tepper with Appaloosa Management. Both are multibillionaires. Ackman is currently worth around $4.2 billion, while Tepper's net worth stands close to $20.6 billion. There's also one other common denominator between these two super-wealthy men. Here's the only artificial intelligence (AI) stock that Ackman and Tepper both own. I won't try to keep you in suspense.