Buffett first took a stake in credit card giant American Express way back in 1991. In the roughly 30 years since that initial investment, American Express shares have generated a total return of more than 5,420%, far outperforming the S&P 500’s 1,800% return. American Express’ business took a big hit in 2020 when the health crisis severely impacted spending on travel, entertainment, dining and other categories. However, American Express has been a top economic reopening play in 2021, gaining 40.9% year to date. Buffett now holds 151.6 million shares of AXP stock worth about $26.3 billion.