What happened

Shares of Weight Watchers International (WW -3.80%) were selling off last month on concerns that Oprah Winfrey would play a lesser role in the company, and amid ongoing worries about slowing subscriber growth. According to data from S&P Global Market Intelligence, the stock gave up 23% last month, continuing a slide that began in July.

The chart below shows the stock's trajectory in December. 

WTW Chart

WTW data by YCharts.

So what

Weight Watchers shares started falling on Dec. 14 after The New York Post reported that analysts had become nervous over Winfrey's relative absence as the company's spokesperson and on news that Weight Watchers, which has rebranded to WW, would seek to add new brand ambassadors.  As Winfrey has backed away from the spotlight, subscriber growth has slowed for two straight quarters, and the stock has fallen more than 50% from its peak over the summer.

A man and a woman going for a run and smiling

Image source: Getty Images.

Shortly after that report came out, Weight Watchers announced Kate Hudson, the actress and co-founder of athleisure brand Fabletics, as its new brand ambassador. The weight-loss company said Hudson would appear alongside Winfrey in its upcoming ad campaign. However, that news did little to quell investor discontent as the stock continued to slide over the following week, alongside a sell-off in the broader market.

Now what

In the new year, CEO Mindy Grossman addressed the concerns about Winfrey, rejecting the notion that Winfrey's interest in WW is fading and saying she was prominently featured in its latest ad campaign, which it just launched.

Weight Watchers stock is now down nearly two-thirds from its peak at $105 in July, and the stock looks cheap at a P/E of 14, considering the company's strong profit growth as earnings per share jumped 53% in its most recent quarter. While slowing subscriber growth could be a problem, the concerns about Winfrey seem to be overblown. At this point, the stock may be oversold.

Check out the latest Weight Watchers International earnings call transcript.