Panamsat Holdings Corp. March 17 began trading shares of common stock as part of an initial public offering (IPO). The 50 million shares were priced at $18.00 per share and are being traded on the New York Stock Exchange under the ticker symbol “PA.” The stock was priced below the expected IPO range of $19-$21 per share, and dipped below the offering price during the first day of trading. The stock closed at $17.35 March 17.