Patrick Gaspard, who served as ambassador to South Africa under President Barack Obama, is stepping down as president of George Soros' Open Society Foundations, fueling speculation that he'll join the Biden administration, potentially as Labor secretary.

What to know: Before his stint as ambassador, Gaspard was Obama's political director in the White House, drawing upon his experience in the labor movement to advance Obama's legislative agenda on health care and financial services reform.

• As the head of OSF, Gaspard straddles a broad network of progressive groups, with an annual budget of $1.2 billion.
• Gaspard will be replaced by Mark Mallock Brown, a British former UN diplomat and member of OSF's board.

What they're saying: "I write to share with you that I will leave Open Society at the end of the year," Gaspard wrote to colleagues. "After four profound years of service to this extraordinary institution, and at a critical juncture for the democracy that is my home, I am compelled to charge once more unto the breech in a new political moment."

The big picture: Soros, a Hungarian-born billionaire who survive the Holocaust, has long been a lightning rod and target of conspiracy theories for some conservative groups, who have accused him of funding Black Lives Matters protestors and migration caravans.

• Trump's personal attorney Rudy Giuliani recently questioned Soros's Jewish identity, saying that Soros is “the last person in the world who can claim victimization as being Jewish,” according to Haaretz.