Investigators at Frost Bank discovered that the stolen cards were being used to make $5 contributions to the Paul campaign, in an apparent attempt to test the cards.
Frost Bank refunded money from nearly 100 customers and canceled all 500 of the credit cards that had been stolen from the bank. The Paul campaign tells CBSNews.com it has refunded to the bank the donations from the stolen cards, which amout to about $3,000.
Though Paul's poll numbers in his quest for the Republican presidential nomination are low, his fundraising has been robust. On Monday he raised $4.2 million, a higher one-day total than any Republican hopeful thus far.
Kerri Price, assistant director of communications for the Paul campaign, noted that the donations from the stolen cards represent "a very small percentage of money that was brought in."
"We don't know anything about the criminals that did this," she said, adding that the tactic was "fairly common with identity thieves."
Added Paul spokesman Jesse Benton: "Ron Paul does not have anything to do with this."