Rex Tillerson
Rex Tillerson
Company: Exxon Mobil
Fortune 500 rank: 1
Total 2011 political contributions: $42,800
Largest contribution: $30,800 to the National Republican Senatorial Committee

Exxon Mobil is no stranger to lawmakers. The energy giant has a long history of lobbying to expand drilling access to federal land, as well as influencing energy and climate policies. In 2011, the gas and oil company spent $12.7 million on lobbying efforts and has spent more than $4 million on special-interest lobbying in the first few months of 2012.

It's no wonder then that CEO Rex Tillerson has made a few key bequests of his own. While Exxon Mobil racked up $226,700 in 2011 campaign contributions, Tillerson donated almost $43,000 of his own money to the Republican National Committee and GOP candidates, including presidential challenger Mitt Romney and Kentucky Senator Mitch McConnell.

--Source for all dollar amounts:, the political contribution tracking arm of The Center for Responsive Politics, a non-profit, nonpartisan research group. All dollar amounts quoted are as of May 3, 2012

By Sierra Jiminez, reporter - Last updated May 07 2012: 7:31 AM ET