Most actively traded companies on the TSX, TSX Venture Exchange

TORONTO - Some of the most active companies traded Monday on the Toronto Stock Exchange and the TSX Venture Exchange:

Toronto Stock Exchange (14,530.91 down 2.66 points):

Fortis Inc. (TSX:FTS.IR). Utilities. Unchanged at $36 on 5.4 million shares.

Osisko Mining Corp. (TSX:OSK). Miner. Down 11 cents, or 1.38 per cent, to $7.87 on 5.03 million shares.

Nautilus Minerals Inc. (TSX:NUS). Miner. Up 19 cents, or 39.58 per cent, to 67 cents on 4.3 million shares.

Bombardier Inc. (TSX:BBD.B). Aerospace. Up four cents, or 0.98 per cent, to $4.13 on 4.07 million shares.

Barrick Gold Corp. (TSX:ABX). Miner. Down 62 cents, or 3.14 per cent, to $19.12 on 3.4 million shares. Newmont Mining Corp. and Barrick blamed each other Monday for the collapse of merger talks that could have combined two of the world's largest gold producers.

Yamana Gold Inc. (TSX:YRI). Miner. Down 19 cents, or 2.27 per cent, to $8.19 on 3.2 million shares.

Toronto Venture Exchange (1,009.58 down 4.01 points):

Petroamerica Oil Corp. (TSXV:PTA). Oil and gas. Down 2.5 cents, or 7.69 per cent, to 30 cents on 8.4 million shares.

Fission Uranium Corp. (TSXV:FCU). Miner. Down five cent, or 3.82 per cent, to $1.26 on 5.08 million shares.

Companies reporting major news:

CGI Group Inc. (TSX:GIB.A). Technology. Down 23 cents, or 0.60 per cent, to $37.91 on 974,324 million shares. The Montreal-based company is establishing a new IT services centre in southwest Louisiana that will eventually have up to 400 employees.

Precision Drilling Corp. (TSX:PD). Oil and gas services. Down 14 cents, or 1.01 per cent, to $13.70 on 2.7 million shares. The share price fell despite an improvment in first-quarter net earnings to $102 million, or 35 cents per diluted share, from $93 million or 33 cents per diluted share a year ago. Revenue was also higher, up 13 per cent to $672 million, mainly due to higher pricing and drilling activity in Canada, the U.S. and elsewhere.

Quebecor Inc. (TSX:QBR.B). Communication Services. Up 12 cents, or 0.45 per cent, to $26.62 on 104,304 shares. The company announced after markets closed that its president and CEO, Robert Depatie, has announced his intention to retire for undisclosed health reasons. His successor as president and CEO of Quebecor and Quebecor Media is Pierre Dion, who has been a member of Quebecor Media's executive committee since 2004. The hand-over is effective immediately but Depatie will remain to oversee the transition in support of Dion until May 30.

Sherritt International Corp. (TSX:S). Miner. Unchanged at $4.67 on 977,828 shares. A dissident group of shareholders seeking three seats on the Sherritt International board of directors believes chief executive David Pathe needs to be replaced. The dissidents, led by investment firm Clarke Inc., say costs are up and the share price has fallen since Pathe took the helm of the mining company at the beginning of 2012.