Wasn't 100% sure about the circuit breaker rules, but his is what I found at wikipedia..... Expect to see it invoked at some point today.
"'Following the Black Monday market crash in 1987, NYSE imposed trading curbs to reduce market volatility and massive panic sell-offs. Following the 2011 rule change, at the start of each trading day, the NYSE sets three circuit breaker levels at levels of 7% (Level 1), 13% (Level 2), and 20% (Level 3) of the average closing price of the S&P 500 for the preceding trading day. Level 1 and Level 2 declines result in a 15-minute trading halt unless they occur after 3:25pm, when no trading halts apply. A Level 3 decline results in trading being suspended for the remainder of the day.[31] (The biggest one-day decline in the S&P 500 since 1987 was the 9.0% drop on October 15, 2008.)"
It’s -599 now....
I don’t know if there are breaks before the market opens.
It appears to be dropping 100 points per hour.
So we should be at -600 at the open of the market.
thanks for the info, might be an interesting day today.