WASHINGTON—President Donald Trump’s company last week donated its 2017 profits from foreign governments to the U.S. Treasury, the company said Monday, but declined to give any details on the size of its contribution or how it determined that number.

George Sorial, chief compliance counsel for the Trump Organization, said that the company had made its donation on Thursday, “calculated in accordance with our policy and the Uniform System of Accounts for the Lodging Industry.” Mr. Sorial noted the donation was “voluntary” and...