
Prachai said at the time there was no cap in making contributions to a party. The funds were meant for publicity campaign, he added.
He was the former leader of Matchima Thipataya Party. Before entering politics, he was the founder of TPI Group, an industrial conglomerate.
The cap has been imposed by the 2007 Constitution limiting the contributions to Bt10 million per corporate contributor.
Prachai paid under the rules of the suspended 1997 charter.
Election Commission member Sodsri Satayatham said under the old rules, party contributions had not been capped and not subjected to audit by the EC.
The opposition Pheu Thai Party has threatened to censure the Abhisit Vejjajiva government on suspicious contributions.