North American stock exchanges posted moderate losses in the opening half hour of trading Tuesday, as investors continued to fret about the Chinese government's early moves to tighten credit.

In Toronto, the S&P/TSX shed 69.05 points to 11285.46. Oil, mining and financial stocks led the retreat. Commodity producers are caught in the downdraft from China, which is trying to cool its economic growth by limiting the amounts banks can loan. Energy company stocks are responding to declining prices for crude.

Suncor Energy and Teck Resources declined more than 1 per cent in the opening minutes. Royal Bank, CIBC and Bank of Montreal slipped nearly 1 per cent.

In New York, the Dow Jones industrial average dipped 27.58 points to 10169.28 and the broader S&P 500 lost 5.74 points to 1091.04.

Leading the decliners, shares of materials giant U.S. Steel tumbled 10 per cent. The selloff is exacerbated by the company's quarterly earnings miss announced this morning. Freeport-McMoRan, one of the world's largest copper producers, fell 4 per cent.

The price of a barrel of crude is down $1.11 to $74.15. An ounce of gold is selling for $6.10 less, at $1,089.60.

With commodities on the decline, the Canadian dollar is taking a beating. The loonie has fallen 0.52 cents to 93.99 cents (U.S.).