SAN JOSE, Calif. ( TheStreet -- eBay ( EBAY) announced that one of its top executives is leaving the company and that it has commenced a search to find someone to head the firm's key Marketplaces division. Lorrie Norrington, president of eBay Marketplaces, will be leaving the company for personal family reasons, according to a statement released after market close on Tuesday. Marketplaces, which includes eBay, Shopping.com, StubHub, Kijiji and a number of other e-commerce sites, is the heart of the retailer's business. Locked in a fierce battle with Amazon ( AMZN), Google ( GOOG) and Yahoo! ( YHOO), Norrington's departure comes at a crucial time for eBay. A five-year eBay veteran, Norrington has led eBay Marketplaces since July 2008 and oversaw a series of major improvements, including search and site technology enhancements. These include the launch of eBay Buyer Protection and eBay Fashion, as well as features that make it easier to identify top-rated sellers. eBay is conducting an external search for Norrington's successor. The global Marketplaces management team will report to eBay CEO John Donahoe until the appointment is made. In a separate regulatory filing, eBay explained that Norrington's separation date will be March 3, 2011. eBay also updated its third-quarter guidance after market close, explaining that its results will be near the high end of its forecast. In July the company predicted third-quarter revenue between $2.13 billion and $2.18 billion. Excluding items, eBay expects earnings between 35 cents a share and 37 cents a share. Shares of eBay dipped 12 cents, or 0.49%, to $24.62 in extended trading. --Written by James Rogers in New York. >To follow the writer on Twitter, go to http://twitter.com/jamesjrogers.