The Twitter logo is displayed ahead of the company's IPO on the floor of the New York Stock Exchange, November 6, 2013. Twitter Inc priced its initial public offering above its expected range to raise at least $1.8 billion, in a sign of strong investor demand for the most highly anticipated U.S. public float since Facebook Inc. REUTERS/Brendan McDermid (UNITED STATESBUSINESS - Tags: BUSINESS SCIENCE TECHNOLOGY)