Never mind finding coal in your stocking for the holidays. Wall Street investors scored a rare — and unwanted — gift this year.

The S&P 500 index SPX, +0.29% fell by 2.7% Monday, marking the first session before Christmas that the broad-market benchmark has booked a loss of 1% or greater — ever.

Bespoke Investment Group spotlighted this dubious S&P 500 record earlier in the day: