What was the market cap when he invested in it?
You could throw a dart at a large cap tech stock and have a 95% chance of outperforming IBM.
Irrelevant. Buffet bought IBM in 2011 with the intention that the stock either languished or declined so he could buy more as IBM repurchased more and more of its own shares. Which it did. He said so himself in 2011 when he bought the shares, describing his intentions.
"Our quiz for the day: What should a long-term shareholder, such as Berkshire, cheer for during that period? I won't keep you in suspense. We should wish for IBM's stock price to languish throughout the five years.The logic is simple: If you are going to be a net buyer of stocks in the future, either directly with your own money or indirectly (through your ownership of a company that is repurchasing shares), you are hurt when stocks rise. You benefit when stocks swoon. Emotions, however, too often complicate the matter." —Warren Buffet, 2011