Canada's main stock index remained muted on Wednesday, while official data showed the nation's economy likely contracted again in May, following its first decline in a year in April.

At 9:39 a.m. ET (1339 GMT), the Toronto Stock Exchange's S&P/TSX composite index was flat at 20,170.36. However, the index is set to mark its fifth consecutive monthly gain.

The energy sector climbed 1.2% as US crude prices were up 0.7% a barrel, while Brent crude added 0.5%.

The nation's economy edged down by 0.3% in April amid lockdowns to slow a harsh third wave of coronavirus infections, Statistics Canada said.

A preliminary estimates by Statistics Canada showed May gross domestic product also likely fell 0.3% on the month.

The materials sector, which includes precious and base metals miners and fertilizer companies, added 0.2%.

On the TSX, 91 issues were higher, while 134 issues declined for a 1.47-to-1 ratio to the downside, with 15.64 million shares traded.

The largest percentage gainer on the TSX was cable operator Cogeco Communications Inc, which jumped 3.9% after unit Atlantic Broadband acquired two service areas from US broadband provider WOW! Internet, Cable & Phone.

The second-biggest gainer was Mullen Group Ltd, which rose 3.8% after the freight transportation provider agreed to buy QuadExpress, the third-party logistics business of Quad/Graphics Inc.

Pot producer Tilray Inc fell 2.5%, the most on the TSX, after brokerage MKM Partners said there are risks surrounding the combined operations of Canadian pot producers Aphria Inc and Tilray Inc that can offset some obvious benefits.

The second-biggest decliner was biotech company Aurinia Pharmaceuticals Inc, down 2%.

The most heavily traded shares by volume were Power Corporation of Canada, Bank of Nova Scotia, and TC Energy Corp.

The TSX posted three new 52-week highs and two new lows.

Across all Canadian issues there were 22 new 52-week highs and nine new lows, with total volume of 28.86 million shares.