President Joe Biden named Allison Herren Lee acting Chairman of the Securities and Exchange Commission (SEC) on Thursday, the agency announced.

Lee was nominated and confirmed to the SEC in 2019 to fill the open Democratic spot on the commission once held by Kara Stein. She succeeds former Chairman Elad Roisman, who was appointed to lead the investment regulator while the agency was heading for transition after Jay Clayton stepped down.

Both Roisman and Lee were nominated by Trump to the US top watchdog, which is legally barred from having any more than three members from either political party.

“It’s an honor to continue my service on the Commission in this new role. I have tremendous respect for my colleagues on the Commission and the exceptional staff across the agency and look forward to working closely with them. Together we will continue the agency’s work of protecting investors and ensuring market integrity,” acting chair Lee said.

Lee specializes in securities law, writing and lecturing around the world about corporate law and financial regulation. She has originally joined the SEC in 2005 and served in various roles for 13 years, mostly as an attorney with the agency’s enforcement arm.

Additionally, Lee was named counsel to former SEC commissioner, Kara Stein, and then as a senior counsel in the Division of Enforcement’s Complex Financial Instruments Unit.

Her long stint with the government service followed seven years in private practice focusing on antitrust, securities and commercial litigation.

“During my time as Commissioner, I have focused on climate and sustainability, and those issues will continue to be a priority for me,” Lee added.

Lee’s nomination comes as a surprise as many reports suggested Gary Gensler, the former Chief of Commodity Futures Trading Commission, was Biden’s likely pick to lead the SEC. Her prospects of winning confirmation are supported by Democrats winning two Senate run-off elections in Georgia this month.

Names floated to replace the former SEC’s Head, Jay Clayton, included Preet Bharara, Manhattan’s former top federal prosecutor under Obama’s administration whom Trump fired in 2017. Lee was among candidates who could be named interim chair as a new chair is considered.