The Truth Laid Bear notes a significant difference in the "quality of disclosure" in reporting presidential campaign contributions. According to current data, the Bush campaign has fully disclosed 93% of its contributors compared to just 76% for the Kerry campaign.
Federal campaigns must make a "best effort" to obtain and report the name, address, occupation and employer of each contributor who gives more than $200 in a calendar year.
One caveat: "Since the data comes from contributors themselves it isn't clear to me whether you can really fault the Kerry campaign for the deficiency --- unless they are supposed to refuse contributions that don't provide adequate disclosure, and that doesn't seem to be the case under FEC regulations as I understand them."