The head of the beleaguered U.S. Postal Service, Louis DeJoy, resigned Monday after nearly five years in the position, leaving as President Donald Trump and Elon Musk’s Department of Government Efficiency have floated the idea of privatizing mail service.

DeJoy had said last month he planned to step down but hadn’t set a date. He leaves an agency with an uncertain future. Trump has said he is considering putting USPS under the control of the Commerce Department in an attempt to stop losses at the $78 billion-a-year agency, which has operated as an independent entity since 1970. It has struggled at times to balance the books with the decline of first-class mail.

Deputy Postmaster General Doug Tulino will take on the role until the Postal Service Board of Governors names a permanent replacement for DeJoy, who became postmaster general in the summer of 2020 during Trump’s first term. He was a Republican donor who owned a logistics business and was the first person to hold the position in nearly two decades who was not a career postal employee.

DeJoy’s tenure was marked by the COVID-19 pandemic, surges in mail-in election ballots and efforts to stem losses through cost and service cuts.

“I believe strongly that the organization is well positioned and capable of carrying forward and fully implementing the many strategies and initiatives that comprise our transformation and modernization, and I have been working closely with the Deputy Postmaster General to prepare for this transition, DeJoy said in a statement.

He added that “much work remains that is necessary to sustain our positive trajectory.”

The National Association of Letter Carriers’ president, Brian L. Renfroe, said in a statement Monday that the union stands ready to work with whomever the board selects as the next postmaster general.

“The future of the Postal Service is on the line, and choosing someone with innovative ideas and appreciation for our Constitutionally mandated service is essential,” Renfroe said.

The Postal Service Board of Governors said in a statement Monday evening that they had retained global search firm Egon Zehnder to help find the agency’s next leader. There’s no established timeline for when the announcement of the next postmaster general will be made, the statement said.

Earlier this month, DeJoy said he planned to cut 10,000 workers and billions of dollars from the USPS budget and he’d do that working with DOGE, according to a letter sent to members of Congress.

USPS workers, including mail carriers, have gathered over the past week to protest the cuts and the plan they say will dismantle the service.

Critics of the plan fear negative effects of the cuts will be felt across the country. Democratic U.S. Rep. Gerald Connolly, of Virginia, has said in response that turning over the service to DOGE would result in it being undermined and privatized.

USPS employs about 640,000 workers who deliver mail, medicine, election ballots and packages across the country, from inner cities to rural areas and far-flung islands.

The USPS has been largely self-funded since 1970. The bulk of its annual $78.5 billion budget comes from customer fees, according to the Congressional Research Service. Congress provides a relatively small annual appropriation — about $50 million in fiscal year 2023 — to subsidize free and reduced-cost mail services.