When the index goes a year without a high, history suggests a rally is around the corner.
Even companies beating estimates have lagged the S&P 500 by 0.6%.
This week's surprise spike could cause some market forces behind this year's rally to switch direction.
Volatility readings have also fallen to the calmest levels seen in over a year.
Gains of 8% or more during that initial period have in the past led to average annual advances of 25%.
History suggests that it's a question of when, not if, the stock market takes a tumble.
When markets have dropped two years in a row, the second year has hurt more.
The constructive view of money managers is at odds with the low gains Wall Street is predicting.
Many strategists remain skeptical that the recent equity gains can last.
Even amid the rout, big tech stocks' earnings don't justify their prices.