After six weeks in office, President Trump has not disclosed the names of the donors who paid for his transition planning, despite a public pledge to do so.

Preparing to take power and fill thousands of federal jobs is a monthslong project that can cost tens of millions of dollars. Previous presidents, including Mr. Trump himself in 2017, used private contributions as well as federal money to foot the bill.

Those presidents made public the names of donors and their contributions within 30 days of taking office, as required under agreements they had signed with the departing administration.

The agreements offered the transition teams millions of dollars in federal funding and a variety of services, such as security, office space and the use of government servers, in exchange for following strict rules on fund-raising, including the disclosure obligation.

Mr. Trump’s 2024 transition team declined to sign such an agreement, stating in late November that it wanted to “save taxpayers’ hard-earned money” by forgoing federal support and financing its operations privately. At the same time, it promised that “donors to the transition will be disclosed to the public” and volunteered that it would “not accept foreign donations.” It did not state whether it would limit individual contributions to $5,000, as previous administrations had.

No disclosures about that financing have been made by the Trump transition, and neither it nor administration officials have given indications of a timeline for releasing that information.