The Dow, which at one point was down more than 600 points, and S&P 500 had their biggest drop since Jan. 3.
Despite fears that President Trump's tariff threat would cause China to cancel this week's talks, the meetings remain on track, according to published reports.
Traders were bracing for a sharp reduction in the global supply of crude oil.
Trading volumes were near their lowest levels in 2019.
The Dow Jones Industrial Average slipped on falling shares of UnitedHealth and IBM, which missed its revenue target in the recently completed quarter.
The tentative conclusions reinforce a widespread perception that the MCAS was to blame for both the Ethiopian Airlines crash and another 737 Max jet crash in Indonesia less than five months earlier that killed all 189 people on board.
The unemployment rate on March 9, 2009, was 8.3 percent; last month it was an enviable 3.8 percent, according to a Labor Department report issued Friday.
All three major equity averages posted their third straight down day.
Spravato is esketamine, which is similar to the party drug and anesthetic known as ketamine.