Trump fared better in Forbes' ranking than he did on Bloomberg's worldwide billionaires list, which puts his net worth at $2.86 billion.
Trump ranked No. 156 in 2016.
Forbes attributed Trump's decline to a weakening NY retail and office real estate market, and new information about his assets.
The magazine further said that the downgrading of his wealth was also a result of "new information" it had collected.
At the top of the list for the 24th consecutive year is the Microsoft founder and serial philanthropist Bill Gates, who has an estimated value of $89bn. It also learned about some debt they pulled down on the Trump International Hotel, adding, "We were able to continue to find more documentation to prove our numbers and give us more comfort in them".
According to Forbes, the White House did not immediately respond to a request for comment on Trump's ranking. Despite a $15.5 billion increase in net worth, Zuckerberg remains in No. 4, worth $71 billion. Entrance to the exclusive club cost a record breaking $2 billion. These include Reed Hastings of Netflix, and Bert "Tito" Beveridge of Tito's Handmade Vodka.
Larry Page, who went to Michigan State University and is involved with Google, is 9th on the list worth $38.5 billion. The cost of admission to the Forbes 400 list hit a record-high of $2 billion in 2017, up from $1.7 billion in 2015 and 2016.