U.S. stocks began the third quarter with more selling, after disappointing reports on jobs, housing and manufacturing deepened concerns about the economy.
At midday, the Dow Jones industrials are down 94 at 9,680. The Standard & Poor's 500 index is down 11 at 1,020, while the Nasdaq composite index is down 22 at 2,088. Canadian markets are closed for the Canada Day holiday and will reopen Friday.
U.S. stocks fell to 10-month lows, with the Standard & Poor's 500 stock index dropping 16 percent from its recent April peak. S&P's financial share index dropped 2.59 percent.
Weak economic data from the United States and China spurred investors to dump shares and oil as concerns harden that the global economy is entering a new downturn.
Initial claims for U.S. jobless benefits rose by 13,000 last week to 472,000. Economists had forecast claims would fall.
The number of buyers who signed contracts to purchase homes fell to a new low in May.
Growth in U.S. manufacturing activity in June slowed to its lowest level since December 2009, while an official survey showed the pace of Chinese manufacturing activity last month was the weakest since February.
The U.S. dollar tumbled against the euro to a five-week low of $1.2473 and hit a seven-month low against the yen.
Oil prices fell for a fourth consecutive day, down 4.5 percent at $72.23 (U.S.) a barrel. Spot gold prices fell $17.25, or 1.39 percent, to $1224.10.
Benchmark 10-year U.S. Treasuries rose 13/32 of a point in price, driving the yield down to 2.892 percent as the grim economic data reinforced low inflation expectations.