Canada's main stock index rose on Wednesday, supported by gains in Cogeco after Altice USA Inc offered to purchase the Canadian television group, while upbeat domestic labor productivity data also bolstered sentiment.

Cogeco's shares rose 30.4%, the most on the TSX, after Altice USA offered to buy the company in a C$10.3 billion ($7.88 billion) all-cash deal.

The country's labor productivity grew by a record 9.8% in the second quarter as hours worked plummeted at a much faster pace than business output, Statistics Canada said.

At 9:45 a.m. ET (1345 GMT), the Toronto Stock Exchange's S&P/TSX composite index was up 26.02 points, or 0.16%, at 16,671.01.

The energy sector dropped 1.3% as US crude prices were down 0.3% a barrel, while Brent crude lost 0.1%.

The financials sector gained 0.6%. The industrials sector rose 0.7%.

The materials sector, which includes precious and base metals miners and fertilizer companies, lost 2.0% as gold futures fell 1.0% to $1,948.3 an ounce.

On the TSX, 110 issues were higher, while 106 issues declined for a 1.04-to-1 ratio favouring gainers, with 18.19 million shares traded.

Cogeco's gains were followed by Alimentation Couche-Tard Inc, which rose 6.2% after the company reported upbeat quarterly results.

Ballard Power Systems Inc fell 6.1%, the most on the TSX, and the second biggest decliner was First Majestic Silver Corp, down 5.5%

The most heavily traded shares by volume were Cardinal Resources Limited, and D-BOX Technologies Inc.

The TSX posted six new 52-week highs and no new lows.

Across all Canadian issues there were 60 new 52-week highs and six new lows, with total volume of 41.41 million shares.