TORONTO - Canadian Satellite Radio Holdings officially started trading today at $16 per share the company announced Monday. The company – which does business as XM Canada – raised $55-million with its initial public offering. The first day of trading, however, saw the market shave $1.75 (11%) from the opening price, closing at $14.25. It also means that with over 20 million shares outstanding, the company is worth nearly $300 million, on paper. Its trading symbol is XSR.SV.