9. Is there a ban on donations from corporations with government contracts to political parties?

Paragraph 441c (a) It shall be unlawful for any person— (1) Who enters into any contract with the United States or any department or agency thereof either for the rendition of personal services or furnishing any material, supplies, or equip ment to the United States or any department or agency thereof or for selling any land or building to the United States or any department or agency thereof, if payment for the performance of such contract or payment for such material, supplies, equipment, land, or building is to be made in whole or in part from funds appropriated by the Congress, at any time between the com mencement of negotiations for the later of (A) the comple tion of performance under; or (B) the termination of negotiations for, such contract or furnishing of material, supplies, equipment, land, or buildings, directly or indirectly to make any contribution of money or other things of value, or to promise expressly or impliedly to make any such contribution to any political party, committee, or candidate for public office or to any person for any political purpose or use; or (2) knowingly to solicit any such contribution from any such person for any such purpose during any such period.

United States Code, Title 2, The Congress. 

It is prohibited for any person who enters into any contract with the United States or any department or agency thereof, entailing the provision of goods and/or services to the federal government to make any contribution to any political party, committee or candidate in connection with a federal election.

GRECO (2011), Evaluation Report on the United States of America Transparency of Party Funding (Theme II), p.14.