No prices can trade below that threshold, only at higher prices than that down 5% limit.

Dow Jones Industrial Average futures were off by more than 1,000 points, triggering the limit down level. S&P 500 and Nasdaq 100 futures were also at their downside limits.

This led traders to look at the SPDR S&P 500 ETF Trust (SPY) — which tracks the S&P 500 — for a better indication of how the market will open. The SPY ETF plummeted 10% in the premarket, signaling that a “circuit breaker” will be triggered shortly after the regular session starts. ETFs that track the Dow and Nasdaq 100 — the SPDR Dow Jones Industrial Average ETF Trust (DIA) and Invesco QQQ Trust — were also down more than 8%.

The ETFs briefly pared losses after the International Monetary Fund said it is ready to mobilize $1 trillion in lending capacity to fight the virus.

While the central bank’s actions may help ease the functioning of markets, many investors said they would ultimately want to see coronavirus cases peaking and falling in the U.S. before it was safe to take on risk and buy equities again.