Date Made / Date Received
Under FEC rules, the date a donor makes a contribution to a candidate and the date the campaign receives it are both important, but for different reasons.
The date a contribution is made determines which per-election limit the contribution counts against. For example, an undesignated contribution made (i.e., postmarked or hand-delivered) on or before the date of the primary election counts against the donor’s limit for that election. Undesignated contributions made after that date count toward the limit for the candidate’s next election (e.g., the general election).
The date a campaign receives a contribution is the date it lists on its FEC reports. For example, campaigns will include on their upcoming Year-End reports (due January 31) only those contributions received by December 31 (the close of books for that report). A contribution received on January 1 will be reported on the committee's first report covering 2012 activity, even if the contribution was made in 2011.
More information on "Date Made" and "Date Received" may be found on page 23 of the Campaign Guide for Congressional Candidates.