Who's trading on the TSX

Some of the most active companies traded Thursday on the Toronto Stock Exchange and the TSX Venture Exchange:

Toronto Stock Exchange (11,811.38 down 118.41 points):

Bombardier Inc. (TSX:BBD.B). Transportation equipment. Down 20 cents, or 6.27 per cent, at $2.99 on 43,606,744 shares. The train and plane maker's stock closed at its lowest since March 2009. On Wednesday, Standard and Poor's rating agency downgraded Bombardier's long-term corporate rating one notch due to weak third-quarter results.

Poseidon Concepts Corp. (TSX:PSN). Fluid handler. Down $8.22, or 62.18 per cent, at $5 on 24,650,529 shares. The stock dropped 62 per cent after the Calgary company reported weaker quarterly results and lowered earnings and spending expectations for the remainder of the year.

Eastern Platinum Ltd. (TSX:ELR). Oil and gas. Down a penny, or 7.14 per cent, at 13 cents on 13,128,740 shares. The stock of the Vancouver-based miner plunged to its lowest level since early 2000 a day after reporting it swung to a loss in the third quarter as revenue dropped 40 per cent amid lower metals prices and fewer ounces sold.

Manulife Financial Corp. (TSX:MFC). Insurer. Down two cents, or 0.17 per cent, at $11.94 on 5,011,698 shares. The financial sector dropped 0.75 per cent to 178.04 points.

Second Wave Petroleum Inc. (TSX:SCS). Oil and gas. Down 25 cents, or 30.12 per cent, at 58 cents on 3,727,127 shares. The Western Canada-focused oil and gas producer reduced its 2012 capital and production guidance due to weak commodity prices and production delays. Second Wave posted a $3.2-million net loss in the third quarter, a reversal from year-earlier profit of $899,000 in the same 2011 quarter despite a 38 per cent jump in revenue.

Progress Energy Resources Corp. (TSX:PRQ). Up 59 cents, or 3.04 per cent, at $19.98 on 3,625,033 shares.

TSX Venture Exchange (1,222.70 down 35.99 points):