The debut of Imperva onto the New York Stock Exchange (NYSE) on Wednesday led to strong trading gains for the maker of software protection against hackers and data theft. On a day which saw Dow stocks decline by more than three percent, the initial public offering of the Redwood Shores, Calif.-based company saw a 33 percent gain over its $18 a share opening, closing at $24 a share. Five million shares were traded, which resulted in the raising of around $90 million. Imperva, founded in 2002, has never been profitable. However, the company experienced a 72 percent jump in revenue between 2008 and 2010, and sales continued spurting this year. According to a company prospectus, in the nine months ended Sept. 30, net revenue rose 43 percent to $55 million compared to the same period of 2010. Imperva's principal R&D facilities are based in Israel.