Tennessee Gov. Bill Haslam is now the richest elected official in America, according to Forbes.

Since August, Gov. Haslam has seen his net worth more than double, from $980 million to an estimated $2 billion. Forbes cites falling gas prices for Haslam’s financial success this year.

Gov. Haslam’s father, Jim Haslam II, founded Pilot Flying J in 1958, which is headquartered in Knoxville, Tenn. Haslam’s brother Jimmy is the current CEO of Pilot, but the governor still owns 15% of the $38 billion truck stop giant.

More people have been filling up, along with buying snacks and drinks, at Pilot’s gas stations thanks to cheap, unleaded gas. Pilot Flying J’s 12-month operating income has grown from $1.1 billion in August to $1.4 billion, reports Forbes.

Despite significant growth, the past couple years haven’t been easy for Pilot. In April 2013, dozens of FBI and IRS agents raided Pilot’s west Knoxville-based headquarters and several nearby offices, seizing thousands of documents and copying computer hard drives.

The company settled last July, admitting that it shortchanged trucking companies on rebates. As part of the agreement, Pilot agreed to cooperate with the ongoing criminal investigation and pay $92 million in fines over the next two years.

The governor, who was Pilot’s president from 1995 to 1999, wasn’t involved with management during the time of rebate scheme. Jimmy Haslam, who is also owner of the Cleveland Browns, has denied any knowledge of the scheme. (Forbes)