Markets have large declines this week
The Dow Jones Industrial average lost 530.94 points, or 3.1 percent, to 16,459.75.
The Standard & Poor's 500 index dropped 64.84 points, or 3.2 percent, to 1,970.89.
The Nasdaq composite fell 171.45 points, or 3.5 percent, to 4,706.04.
Wise Owl