The billionaire investor shrewdly initiated a big position in Nvidia in the first quarter of 2023. By the end of the year, the chipmaker's shares had more than tripled. Nvidia ranks as the fourth-largest position in Tepper's Appaloosa Management portfolio. Tepper loaded up on several artificial intelligence (AI) stocks in the fourth quarter of 2023. However, Nvidia wasn't one of them. He slashed Appaloosa's position in the stock by nearly 23%. Here are the three AI stocks the hedge fund manager bought the most in Q4. Oracle (NYSE: ORCL) wasn't in Appaloosa's portfolio before Q4.