See “conduit contribution”: "Here’s how a “conduit contribution” works. Person A wants to give a lot of money to Candidate X. But federal law puts a ceiling on how much one person can contribute to a candidate. To get around the law, Person A goes to Friend B or Employee C or Associate D and says, “Hey, if you give me the money for Candidate X, I’ll pass along your check and then reimburse you out of my own pocket or from corporate funds.” The friend, employee, or associate effectively becomes a “conduit” for the real contributor, thus the name."

"The law is clear: Under the Federal Election Campaign Act, making campaign contributions in the name of another person or otherwise concealing the true source of the funds is a felony if the contribution exceeds $2,000. In fact, both the person soliciting the contribution and the person who agrees to be reimbursed for it could be investigated. Even if neither is aware of the law."

source: http://www.fbi.gov/news/stories/2007/december/electfraud_121...