Donald Trump's fortune has fallen by an estimated US$200 million ($283.5m) since he took office, according to Forbes magazine, plunging him more than 200 rungs down the worldwide wealth rankings.
Trump was ranked at No. 544 on the magazine's annual richlist, with a net worth of around US$3.5 billion ($5b).
The magazine said that falling house prices in Manhattan, where Trump's former campaign headquarters at Trump Towers is situated, had eaten away at the president's fortunes.
Trump also spent millions of dollars on his campaign, which he claims to have self-funded, though this is fiercely disputed.
"Although Donald Trump's name is plastered on buildings all around the world, his core assets are still located in a small part of New York City," said Dan Alexander, an associate editor at Forbes Media.
"Profits are down at Trump Tower, and the overall neighbourhood surrounding has been struggling over the last year. Since Trump owns so many buildings in such a small area-including Trump Tower, Trump International Hotel & Tower, NikeTown and 1290 Avenue of the Americas-the softening of the market has impacted his net worth more than anything else over the last year."
For the fourth time in a row, Bill Gates was named as the richest man in the world, with an estimated fortune of US$86b ($122b), while Warren Buffett came in at second place with a net worth of US$75.6b ($107b).
Amazon's chief executive Jeff Bezos came in third place, with US$72b ($102b) - up from US$27b ($38b) the previous year, making him the biggest wealth gainer on the list.
He was followed by Zara boss Amancio Ortega with US$71.3b ($101b), and then Facebook founder Mark Zuckerberg in fifth place with an estimated value of US$69.1b ($98b).
Kiwi billionaire Graeme Hart was ranked at No 133 with a net worth of US$9.5b ($13.5b).
In October 2016, Forbes had put Trump's wealth at around US$4.5b ($6.4b), placing him at No 324 on the list.
Both figures are dramatically lower than Mr Trump's own assessment of his fortune, which he claimed was around US$10b ($14b) in 2016.
"I have built an incredible company and have accumulated one of the greatest portfolios of real estate assets, many of which are considered to be among the finest and most iconic properties in the world," he said during the election campaign.
"Booming stock markets, higher commodities prices and plain old-fashioned entrepreneurship helped make this a record year in terms of wealth creation around the globe," a Forbes media spokeswoman said.