A Long but Shallow Decline

The S&P 500 index staged a late-session collapse on Friday to fall for its ninth session in a row, That's the longest streak of declines since 1980. The last time the S&P 500 fell for 10 days? All the way back in 1975. The record is 12 days, hit back in 1966.

But it's easy to make too much of that. The declines have been persistent but very shallow: The S&P 500 is down just 3.1 percent during the slide. Back in 1980, that nine-day streak amounted to losses of 9.4 percent, according to S&P Dow Jones Indices.

Or you can look at it this way: The S&P is down 3.1 percent over the past nine days. But there have been 298 single days where the index suffered bigger declines than the last nine days combined.