What: Shares of Weight Watchers International (NYSE:WTW) dove 44.3% last month, according to data provided by S&P Global Market Intelligence, as the excitement around Oprah Winfrey's involvement with the company faded.

WTW Chart

WTW data by YCharts.

So what: Weight Watchers' stock price more than doubled the day Oprah announced that she had acquired a 10% stake in the company back in October. The stock would go on a massive run and nearly quadruple in value from its price on the day prior to Oprah disclosing her stake.

WTW Chart

WTW data by YCharts.

In December, however, the stock entered into a vicious decline, in which it would lose nearly 60% of its value in the subsequent two-and-a-half months.

WTW Chart

WTW data by YCharts.

Now what: Investors' excitement for the stock reached a fevered pitch in late 2015 amid speculation that the popular celebrity would make a move to take over the company entirely.  As those rumors have subsided, so too has Weight Watchers' share price. Still, Weight Watchers' results will no doubt benefit from having Oprah as a major shareholder and endorser of the company's products. It just may not move the needle enough to justify a 290% jump in share price, as many investors have come to realize in recent weeks.

Joe Tenebruso has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.