Winfrey's stake in Weight Watchers was valued at $ 160.18 million when the markets ended Tuesday. It declined rapidly as the company released its earnings after the markets ended, and dropped to $ 112.1 million, deleting $ 48 million in value within minutes of trading.
However, Winfrey's original investment is still in the black. She bought 6.4 million shares of Weight Watchers at $ 6.79 per share in October 2015, worth $ 43.2 million at that time, according to a Securities and Exchange Commission filing. She also joined the company's board.
Last year, Winfrey sold some of her stake in the company. She now has 5.4 million Weight Watchers shares, according to a January SEC filing.