WASHINGTON U.S. Trade Representative Ron Kirk said on Thursday he was serving his last day in the job and that a top deputy, Demetrios Marantis, would take over as acting trade chief until a replacement is nominated and confirmed by the Senate.
"Demetrios has been a leading voice for President (Barack) Obama's trade policies in Asia and Africa, and he has been instrumental in successes from the completion of the U.S.-Korea trade agreement to the advancing of the Trans-Pacific Partnership and beyond," Kirk said in a statement.
Kirk had previously announced plans to leave by the end of February, but served an additional two weeks.
Obama has not yet nominated a new trade representative.
Acting White House Budget Director Jeffrey Zients has been considered a leading candidate for the job, but appears to have run into opposition from Senate Finance Committee Chairman Max Baucus, a Montana Democrat whose panel would consider the nomination.
Writing in the Financial Times earlier this month, Baucus said the next trade representative should be "an experienced leader with proved mastery of the details of trade negotiations," a description at odds with Zients background as a business consultant.
Zients also ruffled feathers on the Senate Finance Committee by proposing to move the Office of the U.S. Trade Representative into a revamped Commerce Department.
That plan threatens the Finance Committee's jurisdiction over the agency and has gone nowhere in Congress.
Another Baucus line about the need for a trade representative "who is ready to put in the miles to meet counterparts abroad and who is ready to empower staff" has been seen by some as a recommendation for Marantis, who formerly worked for Baucus on the Senate Finance Committee, has traveled extensively in Asia and Africa and is well liked in the agency and in Congress.
Others mentioned as possible nominees include Commerce Undersecretary Francisco Sanchez, Treasury Undersecretary Lael Brainard, White House international affairs adviser Michael Froman and Export-Import Bank President Fred Hochberg.
Sanchez is also believed to be under consideration for secretary of transportation in a competition with National Transportation Safety Board head Deborah Hersman.
Hochberg said this week he would like to continue serving in the administration and believed Obama was in the process of finalizing his remaining economic and trade nominations.