As Weight Watchers tries on a slimmed-down new name, WW, and repositions itself with a focus on wellness, media mogul Oprah Winfrey — the company's second-largest stakeholder — has seen her investment shrink by more than $500 million.

Since last September, when Weight Watchers announced it would change its name to WW and use a new tagline — "Wellness that works” — the company’s stock has shed 60 percent of its heft, making Winfrey one of its biggest losers.

“Wellness is definitely a different sell. It's going to be a bit more of a crowded space,” said Anthony Campagna, global director of fundamental research at Institutional Shareholder Service. “When you start to think about wellness, a dieting company isn't the first thing that comes to mind. It’s going to take time for that messaging to get out there.”

WW is set to report earnings on Tuesday for the fiscal quarter ending in December and will have to show Wall Street that it is moving full speed ahead. While Oprah has starred in WW advertisements, the company has brought on other celebrity brand ambassadors to be the faces of WW, including DJ Khaled, Kate Hudson, and in the U.K., singer Robbie Williams.

But with the stock tanking, does the company need more of a push from Oprah, who also has a media empire, her own food line and plenty of other investments?

The multitasking billionaire appeared in WW’s winter campaign, but has been silent about the company on social media since December. She last tweeted and posted to Instagram about WW from her personal accounts on Dec. 26.

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“She certainly has a ton of brand influence,” said Campagna. “It's hard to quantify exactly."

A WW representative told NBC News that Oprah "remains an investor, active member of the WW Board of Directors, and an engaged strategic partner."

"In addition, last fall we ran a promotion where people who invite a friend to join WW can enter to win a trip to Maui to meet Ms. Winfrey, and that trip will happen in the coming months," the representative said.

By entering a new category, wellness, WW is also being forced to take on new competitors. Last week, Christina Brathwaite, an analyst at JP Morgan, took the unusual step of downgrading WW stock to underweight. She also mentioned the threat from two competitors, Noom and Diet Doctor.

Noom, which promises “lifelong results,” focuses on helping users make healthy, sustainable shifts in their diet, exercise and mental wellness routines. Diet Doctor, a healthy recipe website, has plans tailored to people following the keto diet.

In addition to facing competitors in a new space, Brathwaite said WW also needs to stop shedding daily active users of its app. Her research showed the number of daily active users on WW’s app declined at the start of the new year, a pivotal time for companies seeking to capture business from the New Year's resolution crowd.

“Looking at recent reviews on the Apple Store for the WW app, we were struck by the shift to negativity in recent reviews. Based on the reviews, we believe problems occurred following an app update over the fall and challenges have persisted since then,” she said. However, WW released an updated app earlier this month that Brathwaite said may address some of the apparent bugs keeping people from using the app.

WW, which trades under the ticker symbol WTW, is expected to report earnings of 60 cents per share on Tuesday. The consensus estimate is for quarterly revenue of $347.19 million, up 11.1 percent from the same time last year, according to Zacks.

The good news for WW is that the company has been in more dire circumstances and managed to pull out off it.

“They went through a period of year-over-year topline declines that began in the mid 2013 time frame,” said Campagna. “Their close in 2015 was the worst, year over year. They have reversed that course.”

There’s even better news for Oprah. While her stake in WW has shrunk, she’s still winning. Her shares in the company, not counting compensation she has received as a director, are worth an estimated $160 million more than when she acquired them, making the investment an overall gain.