Jim Cramer warned investors of a rough U.S. market open after South Korea’s KOSPI plunged 12% amid Middle East conflict.

“Beware of a sloppy opening from the huge decline in the KOSPI led by the memory stocks,” CNBC’s “Mad Money” host Cramer wrote. “Traders there have been raising money by selling U.S. stocks in the first hour of trading.”

Earlier, he had flagged specific names. “Beware of South Korean spillover into our markets,” Cramer posted, naming Western Digital Corp. (NASDAQ:WDC), Seagate Technology Holdings Plc (NASDAQ:STX), SanDisk Corp. (NASDAQ:SNDK) and Micron Technology Inc. (NASDAQ:MU), adding that they were “all still vulnerable.”

KOSPI Suffers 12% Single-Day Rout

South Korea’s benchmark KOSPI plunged 12.06% on Wednesday, closing at 5,093.54 — a drop of 698.37 points. That followed a 7.2% decline on Tuesday.

The two-day rout triggered a 20-minute circuit-breaker halt early in Wednesday’s session. Heavyweights Samsung Electronics Co. (OTC:SSNLF) , SK Hynix Inc. and Hyundai Motor Co. (OTC:HYMLF) led the sell-off.

The iShares MSCI South Korea ETF (NYSE:EWY) mirrored the selloff, tumbling 11.40% to close at $132.34.

Futures Defy the Gloom For Now

Despite Cramer’s caution, U.S. futures were pointing higher on Wednesday morning.

Nasdaq-100 Futures were up 0.35% to 24,842.50. S&P 500 Futures added 0.26% to 6,842.25.

The Invesco QQQ Trust, Series 1 (NASDAQ:QQQ) was up 0.44% at $604.22 in Wednesday’s premarket trading, while the State Street SPDR S&P 500 ETF Trust (NYSE:SPY) gained 0.33% to $682.55 ahead of the open.

Oil Rally Pauses Below $75

WTI crude futures slipped below $75 a barrel on Wednesday after a nearly 14% three-day surge to a one-year high, driven by fears that a U.S.-Israeli campaign against Iran would disrupt Middle East supply, according to Trading Economics.

Gains cooled after President Donald Trump said the U.S. Navy would escort tankers through the Strait of Hormuz and provide political risk insurance for shipments through the vital waterway.

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