President-elect Donald Trump sold all of his stockholdings in June, a transition spokesman said, removing himself from positions in numerous U.S. companies.

The revelation came on Tuesday from Jason Miller, a spokesman for Mr. Trump, during a phone call with reporters. He was asked about Mr. Trump’s past holdings in Boeing Co., a company the president-elect had criticized earlier in the day for what he alleged were high costs for the next Air Force One.

“The...