Richard 'Dick' Costolo, chief executive officer of Twitter Inc.,... News PhotoCEO,CFO,Dick Costolo,Finance,Initial Public Offering,Internet,Leaving,North,North America,Online Messaging,Philadelphia - Pennsylvania,Ritz Carlton Hotel,Social Networking,Stock Market and Exchange,Technology,The Americas,Twitter,USA,VerticalPhotographer Collection: Bloomberg 2013 BloombergRichard 'Dick' Costolo, chief executive officer of Twitter Inc., left, and Mike Gupta, chief financial officer of Twitter Inc., depart the Ritz-Carlton Hotel in Philadelphia, Pennsylvania, U.S., on Monday, Oct. 28, 2013. The San Francisco-based company is seeking a valuation of 9.5 times 2014 sales in its IPO next month, according to data released in a filing with the Securities and Exchange Commission and analyst projections compiled by Bloomberg. Photographer: Jim Graham/Bloomberg via Getty Images