Nvidia stock rises as AI chipmaker plans huge stock buyback

AI chipmaker Nvidia (NVDA) signaled Monday that it believes its shares are undervalued as it announced a big increase in its stock buyback program. Nvidia’s board authorized a $150 billion increase in its stock repurchase plan, bringing the total remaining amount of the program to $235 billion. The Santa Clara, Calif.-based company said it plans to run the remaining total…