The auto insurer Geico on Monday named Todd Combs, one of Warren Buffett's portfolio managers at Berkshire Hathaway Inc, as its chief executive.

Combs, 48, will take over on Jan. 1, 2020, replacing Bill Roberts, who became chief executive in June 2018 and will become a Geico vice chairman. Roberts had succeeded his longtime predecessor Tony Nicely, who remains Geico's executive chairman.

The change adds to Combs' responsibilities at Berkshire, which he joined in 2010, and where he will continue to oversee about $14 billion of investments.

Many investors consider Combs and Buffett's other portfolio manager, Ted Weschler, the top candidates to succeed Buffett as the Omaha, Nebraska-based conglomerate's chief investment officer.

Combs is also a director at JPMorgan Chase & Co and helped spearhead the creation of Haven, the venture among Berkshire, JPMorgan and Amazon.com Inc to reduce employee healthcare costs.

Berkshire and Geico did not immediately respond to requests for comment.

Nicely said in a statement that Roberts, a 35-year Geico veteran, told him in early November that he was about to turn 70 and intended to retire at the end of 2020.

Roberts joined Geico in 1984 in its marketing department, and was a key driver of the insurer's humorous advertising, which rivals such as Allstate, Liberty Mutual and Progressive now also pursue.