TORONTO -- The Canadian dollar fell for a second-day in a row, dropping almost a penny against the U.S. dollar, as it continued to face pressure from weakened commodity prices.

The loonie lost 0.96 of a U.S. cent to close at 77.70 cents US. The drop was in sharp contrast to its performance earlier this week, when it crested 80 cents US in intraday trading.

Commodities were mixed, with the June gold contract falling $17.40 to US$1,274.40 an ounce and July copper contracts down three cents to US$2.19 a pound.

Oil was ahead for the first time in four sessions, adding 13 cents at US$43.73 per barrel. The June natural gas was up five cents at US$2.14 per mmBTU,

Gold, materials and mining stocks weighed on the S&P/TSX index, which pulled back 75.68 points at 13,632.

In New York, the Dow Jones industrial average fell 99.65 points at 17,651.26, while the broader S&P 500 lost 12.25 points at 2,051.12. The Nasdaq composite lost 37.58 points to 4,725.64.