Billionaire oil tycoon Harold Hamm will appear before the Senate Finance Committee today to “warn against nixing oil industry tax breaks”.

While Hamm may these days be known as an energy adviser and fundraiser for Mitt Romney and big donor to Romney’s super PAC, he is also a big giver at the Congressional level, according to our analysis of data from the Center for Responsive Politics.

• Hamm has donated to at least four members of the Senate Finance Committee over the years. Donations include $2,500 in 2011 to Sen. Max Baucus (D-Mont.), $2,000 in 2004 to Sen. John Thune (R-S.D.), $2,000 in 2004 to Sen. Tom Coburn (R-Okla.) and $2,300 in 2009 to Sen. Kent Conrad (D-N.D.).
• The Republican National Committee has received $86,600 from Hamm since 2008. Since 2010, the National Republican Senatorial Committee (NRSC) has received $12,400 from Hamm and the National Republican Congressional Committee (NRCC) has received $33,300.
• Since 2007, Hamm has given over $1.2 million to federal candidates, party committees, and PACs (with $985,000 of that to the Romney-aligned "Restore Our Future" super PAC).