I just calculated the average dip in the week post op ex over the past year and it's 2.8%. There doesn't seem to be any relationship between the op ex week's action and the post op ex, at least in a linear regression with the post op ex week return regressed on the op ex week return.
So, would you say that we're due for a more than average dip during the week?
Also, wouldn't new lows be more likely to expand on the first failed rally off a new high? I would think the first down leg would bring some new lows, but that the real divergence would happen when they tried to rally the indices but couldn't get as many stocks to play along. In that scenario, we wouldn't get that many new lows on the next retreat, but they would continue to expand as the retreat was retraced.