September futures on the S&P/TSX index were down 0.7% at 6:54 a.m. ET (1054 GMT).
Crude prices slid as the downgrade of U.S. government credit weighed on sentiment, while copper prices eased on a dim demand outlook from top metals consumer China after feeble economic data. [O/R] [MET/L]
Gold steadied after data showing a deterioration in euro zone business activity triggered some safe-haven inflows, but held near three-week lows on a stronger dollar and higher bond yields. [GOL/]
Fitch's downgrade of the U.S. credit rating is likely to exacerbate unease about the country's debt position, political polarization and the global standing of the U.S. dollar, investors and analysts said.
Amid the Fitch downgrade turmoil, traders will keenly watch data on initial jobless claims for the week ended July 29, due at 8:30 a.m. ET, to determine the resilience of the U.S. labor market.
Data on Canada's total reserves is also due later in the day.
The Toronto Stock Exchange's S&P/TSX composite index fell to a two-week low on Wednesday.
Greater Toronto Area (GTA) home prices fell in July for the second straight month and home sales tumbled nearly 30% as the Bank of Canada continued to raise borrowing costs.
Among company earnings, Canada's largest oil and gas producer Canadian Natural Resources Ltd posted a second-quarter profit that more than halved.
On Wednesday, Shopify, forecast strong revenue growth and delivered better-than-expected results, while world's biggest fertilizer Nutrien decided to indefinitely pause its ramp-up plans for potash production and halt work on its clean ammonia project at Geismar, Louisiana.
COMMODITIES AT 6:54 a.m. ET
Gold futures: $1,941.4; -0.2% [GOL/]
US crude: $79.28; -0.3% [O/R]
Brent crude: $82.98; -0.3% [O/R]
(Reporting by Siddarth S in Bengaluru; Editing by Milla Nissi)