Shares of Weight Watchers climbed nearly 14 percent at their height on Monday, topping out at about $53.60 apiece.
Winfrey, a significant shareholder as well as the weight loss company's de facto icon, accepted the Cecil B. DeMille Award Sunday night at the 75th annual Golden Globe awards.
The video of Winfrey's speech, which explored issues of race, gender and other social and political hot buttons, went viral. Despite a backstage denial by Winfrey, her speech and subsequent reports fueled speculation that she may be considering a presidential run in 2020.
Oprah has made Weight Watchers an investor magnet since buying a 10 percent stake in the company over two years ago. Her $43 million initial investment of 6.4 million shares in October 2015 more than doubled Weight Watchers stock that same day.
Since then, Winfrey's investment has accumulated value close to $300 million, and the overall stock has shot up more than 350 percent year-to-date.