Update (4:23 p.m. EST): Updated with closing price, day high and low prices, price change and volume information.

NEW YORK (TheStreet) -- Yahoo  (YHOO) fell 1.78% to $40.34, down 73 cents from its previous close of $41.07, at the close of the trading day on Thursday as Chief Operating Officer Henrique de Castro is leaving the company.

The stock had a volume of 15,716,963, just below its average of 16,537,800. It hit a high of $40.75 and a low of $40.11 for the day.

CEO Marissa Mayer brought de Castro into Yahoo from Google  (GOOG) slightly more than one year ago to help the company regain some ground against other Internet entities such as Google and Facebook, and rebuild its core advertising business. Yahoo announced de Castro's termination in an extremely brief document filed with the Securities and Exchange Commission.

"Henrique de Castro, Chief Operating Officer of Yahoo! Inc. (the "Company"), will be leaving the Company effective January 16, 2014," the notice reads. "Mr. de Castro will receive the severance benefits provided for in his Employment Offer Letter, dated October 15, 2012, Severance Agreement, dated February 28, 2013, and equity award agreements."

TheStreet Ratings team rates YAHOO INC as a Buy with a ratings score of B-. TheStreet Ratings Team has this to say about their recommendation:

"We rate YAHOO INC (YHOO) a BUY. This is driven by multiple strengths, which we believe should have a greater impact than any weaknesses, and should give investors a better performance opportunity than most stocks we cover. The company's strengths can be seen in multiple areas, such as its solid stock price performance, reasonable valuation levels and expanding profit margins. We feel these strengths outweigh the fact that the company has had sub par growth in net income."

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