The world’s 500 richest people made more than a quarter trillion yesterday as volatile markets react to fragile Iran war ceasefire

Wall Street traders saw a huge surge yesterday, and the world’s wealthiest billionaires had their best day in nearly a year, after President Donald Trump took back his threat that “a whole civilization will die tonight” on Tuesday, quelling traders’ fears. 

The world’s 500 richest people made $265 billion yesterday, according to the Bloomberg Billionaires Index. With the Dow Jones Industrial Average jumping 2.85% and the S&P 500 soaring by 2.51%, it was the second-largest single-day profit since the index was created in 2012.

Meta CEO Mark Zuckerberg made the most gains and added $12.8 billion to his personal net worth as Meta shares—of which Zuckerberg owns about 13%—rose 6.5%. Luxury goods billionaire Bernard Arnault had the second-highest gains with $9.89 billion. 

The largest gain for the world’s 500 wealthiest people was just a year ago tomorrow, on April 10.  Last year on this day, Trump paused his planned “Liberation Day” tariffs, and the subsequent 24 hours of trading added a record $304 billion to the top 500 wealthiest’s net worths. In comparison, this Wednesday saw 61 people on the index grow their wealth by more than $1 billion. 

The rally won’t offset that the 500 wealthiest billionaires are still at a collective loss of $38.8 billion year-to-date. The world’s richest man Elon Musk alone lost about $3 billion on Wednesday. 

That growth may not last forever. Both the Dow and and S&P 500 briefly dipped this morning before making modest gains as reports of a shaky ceasefire dominated headlines. Crude oil climbed back up to $100 per barrel on Thursday morning, as doubts grow over how the ceasefire will hold. The current price is far from its peak of $118.35 since the war began, but much higher from its $70 cost before the war. 

After an eleventh-hour ceasefire deal between the U.S., Israel and Iran was reached on Tuesday, just before Trump’s self-imposed 8 p.m. deadline that night, a ceasefire agreement sent markets soaring. Then Israel heavily bombarded what it considered Hezbollah strongholds in Lebanon on Wednesday, killing more than 200 people. Iran, which said it believed the ceasefire included Lebanon, claimed Israel had violated the agreement and thus closed the Strait of Hormuz to non-approved ships in response to the attacks. 

On Thursday as talks continue, Trump told NBC News that he asked Israeli Prime Minister Benjamin Netanyahu to be “a little more low-key” in operations in Lebanon.

This story was originally featured on Fortune.com