Hello, this is Anniek Bao writing to you from Singapore. Welcome to another edition of CNBC’s Daily Open.

The dominant story is still the Strait of Hormuz, and it’s getting more complicated by the hour.

Oil has dropped below $100 per barrel on signs that diplomatic efforts for resolving the Mideast conflict are ongoing, even as the U.S. started blockading Iranian ports.

Market wobbled, then rallied on signals that Tehran might still want to talk, with investors assessing the blockade as brinkmanship as expectations for a possible deal rise.

The U.S. Navy began enforcing a blockade against vessels entering and departing Iranian ports on Monday, after peace talks in Islamabad over the weekend ended without a deal.

Tehran has been using its partial control of the Strait of Hormuz to negotiate safe-passage deals with several countries reliant on energy flows through the strategic waterway and continuing oil supplies to its major buyer, China.

“We can’t let a country blackmail or extort the world, because that’s what they’re doing,” Trump said of Iran on Monday.

Asked if the goal of the obstruction was to force Iran to reopen the strait or come to the negotiating table, Trump said, “Both of those things, certainly, and more.”

While Trump had announced the blockading of the Strait of Hormuz, the U.S. Central Command clarified that it will not impede vessels transiting to and from non-Iranian ports.

The West Texas Intermediate was 2.37% lower at $96.73 per barrel as of 8:00 p.m. ET, while Brent crude declined 1.82% to $97.51 per barrel, having gained during US trading hours.

U.S. stocks, meanwhile, climbed overnight, with the S&P 500 rising 1% to its highest level since the war began in late February, after Trump said he had heard from “the right people” in Iran who still want a deal with the U.S., signaling that diplomatic channels haven’t fully closed.

Asset management BlackRock upgraded its outlook for U.S. stocks on hopes that contained impacts from the war and strong corporate earnings will create a favorable backdrop for domestic equities.

The coalition picture around Trump’s blockade effort appears messy. The U.K. pushed back on Trump’s claim that Britain was joining the effort, saying it was working with France to build a “wide coalition” to safeguard freedom of navigation.

And lurking in the background: U.S. intelligence assessment reportedly suggested that China was prepared to supply new air-defense systems to Iran, a development that could complicate relations between Beijing and Washington.

China is expected to release its import-export data for March later on Tuesday, which would offer a glimpse into how the economy has fared under the shadow of the war.

And on the Fed front, the clock is ticking uncomfortably. Fed chair nominee Kevin Warsh has submitted the required paperwork to the Senate, clearing a major hurdle to a confirmation hearing, according to people familiar with the matter.

But whether Warsh gets there before Jerome Powell’s May 15 term expiration is another question entirely.

— Anniek Bao

Trump is blockading Iranian ports in the Persian Gulf. What does that mean?

A former Biden-era Pentagon official said the U.S. is trying to turn the tables on Iran, which has blockaded the strait for weeks during the U.S.-Israeli war with the country, creating a bottleneck that roiled global markets and strained the economy.

Experts say the goal of the blockade is to convince Iran’s leaders to back down and acquiesce to U.S. demands to end the war and restore freedom of navigation to the strait.

“The administration seems to be pursuing what is called a close blockade, which is an attempt to prevent ships from going into those ports or leaving those ports,” said Michael Horowitz, senior fellow for technology and innovation at the Council on Foreign Relations and a former deputy assistant secretary of Defense.

“The theory behind a close blockade of Iran’s ports is to make it impossible for Iran to financially benefit from oil sales via shipping in the strait while it is restricting others from doing so.”

— Garrett Downs