By midday, shares had gained 16.7% to $8.17.
The San Ramon, Calif.-based company priced its 10 million shares at $7, downwardly revised from a previous range of $9 to $11.
In its IPO filings, the company said it has over 2,000 clients including Siemens, Xerox (XRX) and Comcast (CMCSA). In 2013, Five9 recorded revenue of $84.1 million, a 32% year-over-year increase and a net loss of $31.3 million.Must Read: Warren Buffett's 10 Favorite Growth Stocks STOCKS TO BUY: TheStreet Quant Ratings has identified a handful of stocks that can potentially TRIPLE in the next 12 months. Learn more.