Shares of cloud software company Pivotal Software Inc. are up 4.9% in their first day of trading Friday. The stock opened at $16.75, 11.7% above its $15 IPO price. The first trade was executed at 10:43 a.m. ET. Pivotal offered 33,117,000 shares of Class A stock, and selling-shareholder Generic Electric Co. offered 3,883,000 shares of Pivotal's Class A stock, which amounted to about 20% of the company's stake in Pivotal. Pivotal's software helps firms build and deploy their own cloud software. The company has gone public at a time when the Renaissance IPO ETF is up 2.9% and the S&P 500 is up 0.7%.