The Toronto stock market was off to a tepid start to September trading Tuesday while investors wondered what steps central banks might take to support the economic recovery.

The S&P/TSX composite index edged up 0.41 of a point to 11,949.66 while the TSX Venture Exchange gained 2.41 points to 1,243.14 as investors also took in major acquisition activity.

Montreal-based Valeant Pharmaceuticals International Inc. (TSX:VRX) is buying U.S. dermatology products maker Medicis Pharmaceutical Corp. for about $2.6 billion in cash in a deal to strengthen its position in skin treatments and care.

Valeant said Monday that it is paying $44 per share for Medicis, a 39 per cent premium over Friday's closing price of $31.87 for the Scottsdale, Ariz., company. Valeant stock ran up $6.08 or 12.05 per cent to $56.55.

And Toronto-based conglomerate Onex Corp. (TSX:OCX) dipped 12 cents to $38.64 as it announced that it is buying Louisville, Ky.-based SGS International Inc. for $813 million. The company is a provider of packaging graphics services.

The Canadian dollar was ahead 0.1 of a cent to 101.55 cents US amid higher commodity prices.

U.S. markets were listless ahead of the mid-morning release of a key gauge of the manufacturing sector.

The Dow Jones industrials declined 20.52 points to 13,070.32, the Nasdaq composite index was down 2.63 points at 3,064.33 and the S&P 500 index slipped 1.2 points at 1,405.38.

The Institute for Supply Management's index is expected to come in at 50.2, which would signal expansion, up from July's reading of 49.8.

Traders are looking ahead to Thursday and an announcement from European Central Bank president Mario Draghi. He is expected to announce details of a new bond-buying program intended to bring down the borrowing costs of countries such as Spain and Italy.

The plan is a crucial step to easing the crisis, which is increasingly hurting the continent's economy.