Weight Watchers International Inc. shares rose as much as 22 per cent after investor and spokeswoman Oprah Winfrey said she's lost more weight using the program.
"I lost 26 pounds, and I have eaten bread every single day," the entertainment mogul said in a video posted to Twitter.
The shares climbed as high as $13.54 after the video was released, continuing a trend of Weight Watchers' stock rising when Ms. Winfrey's weight goes down. It also climbed in October after she said on the Ellen DeGeneres show that she'd lost 15 pounds (6.8 kilograms).
Investors are betting that Ms. Winfrey can help turn around the company, which has struggled to compete with fitness apps and other programs in recent years. Ms. Winfrey, 61, announced her partnership with Weight Watchers in October, saying she would buy 10 percent of the stock and join the board. In late October, she reported that the stake was almost 15 percent, including options.
Short investors, who bet that stocks will go down, also have targeted Weight Watchers. The company's short interest out of shares outstanding is 16 percent. That puts it in the top 10 percent of most shorted Russell 2000 companies, according to data compiled by Markit Ltd. and Bloomberg. The short interest reached as high as 20 percent on Jan. 19, the most since March 2015, the data show.
Weight Watchers is also one of the most expensive stocks to short. The cost to borrow shares is rated a 9 by Markit, with 10 being the highest. The average for the Russell 2000 is 1.6.
Oprah began appearing in ads endorsing Weight Watchers in December. The latest clip, which she posted with the tweet "Eat bread. Lose weight. Whaaatttt?" focused on her love of bread.
"This is the joy for me," Ms. Winfrey said. "I don't deny myself bread. I have bread every day."