NEW YORK ( TheStreet) -- Apple's ( AAPL) iPhone 5 event, scheduled for Oct. 4, will be held at its own campus in Cupertino, Calif., rather than the Yerba Buena Center for the Arts in San Francisco, where it has held product demonstrations in the past, according to AllThingsDigital. The event will be the first led by new CEO Tim Cook, who replaced Steve Jobs last month. Shares of Apple fell 0.5% to $402.40 in premarket trading on Monday. Groupon lost its chief operating officer after five months on the job, as Margo Georgiadis has returned to Google ( GOOG), her former employer. Georgiadis will become Google's president for the Americas. The daily deals site, which has been criticized recently for altering its accounting metrics to appeal to investors, revealed in an SEC filing on Friday that it had committed an error in the way it reported revenue. Groupon restated its revenue as $688 million, down from $1.5 billion it had originally reported. Google over the weekend issued an updated iOS app for its Google+ social network, just days after launching a new Android version of the app. The app supports Hangouts, which lets users communicate with one another through iPhone cameras, among other updates. Shares of Google rose 0.9% to $530.45 in premarket trading on Monday. Yahoo! ( YHOO) is undergoing a "strategic review" of options, the company said Friday in a memo to employees. The media giant is working with investment bank Allen & Co. to field inquiries from potential bidders, it said. Shares of Yahoo! rose 1.4% to $14.92 in premarket trading on Monday. Popular microblogging site Tumblr has raised $85 million in venture funding, the company announced on Monday. The site, which attracts around 13 billion page views per month, has seen its traffic explode in the past year. Thirty million blogs have been created using Tumblr since the site's launch. --Written by Olivia Oran in New York. >To follow the writer on Twitter, go to http://twitter.com/Ozoran. >To submit a news tip, send an email to: firstname.lastname@example.org.