NEW YORK ( TheStreet) -- SeaWorld Entertainment ( SEAS) was surging after the home of Shamu the killer whale saw its initial public offering priced at the top of its expected range on the New York Stock Exchange Friday. SeaWorld was gaining 22% to $33.48 in midday trading. The Orlando-based amusement park giant, which operates 11 theme parks including three SeaWorld locations and Busch Gardens, is backed by private equity giant Blackstone Group ( BX). Earlier this week, IPO Desktop president Francis Gaskins told TheStreet's Debra Borchardt that SeaWorld will benefit from an improving economy. "Since 2009, their financials have improved because of the improved economic conditions ... recently the revenues of the average monies they get from each attendee is up and their attendance is up." The stock debuted at about $30.56 Friday after pricing its IPO of 26 million shares at $27 a share and raising $702 million. The share prices arrived at the high end of the anticipated $24 to $27 range, bringing the stock's market value to about $2.5 billion and making it one of the biggest private-equity-backed initial public offerings of the year. The company had originally planned to offer 20 million shares. The proceeds will help pay down some of the SeaWorld's debt. Blackstone bought SeaWorld from brewing behemoth Anheuser-Busch InBev ( BUD) for $2.7 billion in 2009. It retains a majority stake in the company after the sale. Follow @atwtseWritten by Andrea Tse in New York >To contact the writer of this article, click here: Andrea Tse.