The Toronto stock market was higher at the open amid rising commodity prices and major acquisition activity.

The S&P/TSX composite index gained 21.59 points to 11,970.85. 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.

The Canadian dollar was ahead 0.1 of a cent to 101.55 cents US.

U.S. markets were listless ahead of the release of a key gauge of the manufacturing sector. The Dow Jones industrials lost 13.32 points to 13,077.52, the Nasdaq composite index was 0.7 of a point higher at 3,067.66 and the S&P 500 index added 0.03 of a point to 1,406.61.

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.

Oil was ahead 21 cents at US$96.68 a barrel.