A trader works on the floor of the New York Stock Exchange in New York City. Photo: AFP / Timothy A. Clary
The biggest S&P500 intraday point swing on recorded happened on Tuesday (NZT).
It followed the second-biggest just a few days earlier.
Data shows that there was a 411.53 point swing on 7 April in the US.
"What's interesting is it's almost twice the size of the previous move of that magnitude which happened last Friday," said Mike Taylor, founder of Pie Funds.
"We are setting records."
The data goes back to 1967.
Taylor said it was an extremely difficult time for fund managers and investors.
"If you compare it to, say, previous events I've lived through - Covid or the global financial crisis, things were evolving and they were, to a point, quite hard to stop. If you think about Covid, it was very scary because at one point we didn't know whether half the world was going to die of a virus.
"With the GFC, we didn't know if the banking system was going to stop and banks wouldn't lend to each other. Here this whole problem could go away if one person decides to take an offramp or make a rational decision. World stock markets, CEOs around the world, countries, are at the mercy or the whim of a couple of people in a tight circle in the White House making this decision."
Dean Anderson, founder of Kernel Wealth, said there were some other factors that affected the points swing.
"This is not percentage change. The nominal value today of the index is much higher than 1967, so the nominal points swing today will be higher.
"However, it doesn't surprise me that there is large intraday swings as the market is trying to digest a whole range of assumptions and are making predictions on what the future looks like."
Taylor said it seemed unlikely that Trump would back down without being able to present his followers with some sort of deal or win.
"Maybe behind the scenes they are looking more at those at the moment. All their messaging to the market is we don't care about you and your investments, we're trying to rewrite the trade balance around the world."
Investors were grappling with deep uncertainty, Taylor said.
He said he hoped that within a couple of months the "headline news" would have died down and people could get on with their lives.
"It probably does bring closer relationships for the rest of the world. There could be an Asian bloc of trading partners. New Zealand will be looking for other places to send our exports."
