The range of closing prices in the S&P 500 Index (SPY) over the last ten days has been less than one percent, one of the lowest readings we've had since March, 2003 (N = 790 trading days). Overall, the average gain for SPY during that period has been .61% (488 up, 302 down).
When we divide the sample in half based on closing trading ranges, however, a pattern shows up. When the ten-day range has been narrow (N = 395), the next ten days in SPY have averaged a gain of only .26% (228 up, 167 down). When the ten-day range has been wide (N = 395), the next ten days in SPY have averaged a rise of .95% (260 up, 135 down).
In general, narrow ten-day ranges have led to subnormal returns ten days later.