Dow futures down nearly 500 pts.
Overnight trading in Asian market took alarming drops.
Stock market already nervous.
Are we headed for a Black Tuesday?
At 6:30 a.m. ET, futures were indicating a disastrous start for stocks. Dow futures were down 4 percent to 11,622 while S&P futures lost 4.3 percent to 1267.50. Such a decline would mark the sharpest drop at the open for U.S. stocks since the first session following the Sept. 11 terrorist attacks.