The legal fund aimed at helping President Trump’s associates with fees related to the Russia investigation raised more than $200,000 through the end of June, mostly from a trio of longtime Trump allies, according to new tax filings reviewed by The Wall Street Journal.

Half of that money came from California real-estate developer Geoffrey Palmer, a longtime friend of Mr. Trump’s, who gave $100,000 on June 30, the final day of the second-quarter reporting period.

Billionaire...