The countdown to Treasury Secretary Timothy Geithner’s long-anticipated departure from the Obama administration became more official on Thursday with a Treasury Department spokeswoman confirming that Geithner still plans to step down later this month. Geithner’s planned exit puts him out before negotiations on the debt ceiling and sequestration are due to heat up in February. With the Senate out until Inauguration Day on Jan. 21, the chamber would be unable to confirm a successor until at least late this month. White House Chief of Staff Jacob Lew is still considered to be the top contender to succeed Geithner.