MW Investors brace for renewed volatility after this weekend's Iran developments

By Mike Murphy

Iran said the Strait of Hormuz is again closed to shipping traffic.

After a three-week-long rally that's brought the S&P 500 to new record highs, investors are again bracing for uncertainty following a whirlwind of weekend developments concerning the war with Iran.

Hopes had been raised last week that the war may soon end, and that the crucial Strait of Hormuz was reopening to shipping traffic. But Iran on Saturday said the strait remained closed, and reportedly fired on two Indian-flagged ships that were forced to turn around.

Iranian officials said Sunday that the strait will remain closed as long as the U.S. continues its blockade of Iranian ports, according to the Associated Press.

Also Sunday, President Donald Trump said a U.S. delegation will return to Islamabad, Pakistan, on Monday for talks on extending the two-week-long ceasefire, which is set to expire this week. Iran, however, had not yet confirmed it would attend the talks.

Trump also renewed threats to bomb Iran's civilian infrastructure if the country's new government doesn't agree to a deal.

"I hope they take it because, if they don't, the United States is going to knock out every single Power Plant, and every single Bridge, in Iran. NO MORE MR. NICE GUY!" Trump said in a Truth Social post Sunday morning.

Trump also posted that the U.S. seized an Iranian-flagged cargo ship in the Gulf of Oman that had tried to run the blockade.

The renewed bluster could derail the market's recovery. Stocks had roared back from March losses triggered by the Iran war.

"That is the problem with trading a tape that is being written in real time by geopolitics rather than grounded in anything stable," Stephen Innes, managing partner at SPI Asset Management, said in a weekend note. "What looked like a clean glide path into the weekend could instead fracture into yet another Monday-open negative feedback loop, where price chases headlines and then headlines chase price. "

Last Wednesday, the S&P 500 SPX closed above the 7,000 level for the first time ever, and notched two more record closes Thursday and Friday. Meanwhile, the tech-heavy Nasdaq COMP posted its 13th straight session of gains, its longest winning streak since 1992. The Dow Jones Industrial Average DJIA saw its best week sine June.

Read more: The S&P 500 blows past 7,000 in an epic comeback rally. Here's why it can keep going.

Crude oil prices ended Friday at five-week lows as tensions had relaxed. West Texas Intermediate crude for May delivery (CLK26) (CL.1) fell 11.5% on Friday, down more than $20 a barrel from earlier last week. Brent crude for June delivery (BRNM26) (BRN00), the global benchmark, closed down 9% on Friday.

Bitcoin (BTCUSD) fell slightly Sunday, and was last trading around $75,000.

Aside from geopolitical developments, investors will also be keeping a close eye on earnings this week. Tesla $(TSLA)$, Intel $(INTC)$, IBM $(IBM)$, Boeing $(BA)$ and United Airlines $(UAL)$ are among the top companies scheduled to report first-quarter results.

-Mike Murphy

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April 19, 2026 15:49 ET (19:49 GMT)

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