The Netherlands-based consortium has bought the club from its South Australian owners including Robert Gerard, who had been a 30 per cent stakeholder.

"It's mainly Dutch people ... they do own football clubs and they wanted to grow their little group of clubs," Gerard said on Wednesday on radio FIVEaa.

The consortium owned other clubs in Holland, France and China, he said.

Football Federation Australia (FFA) on Wednesday ratified the sale.

Gerard had owned a 30 per cent stake in United with the club's chairman Greg Griffin, while Richard Noble and Bruno Marveggio had each had 20 per cent.

The quartet bought the club eight years ago from FFA.

"It was an absolute shambles when we arrived," Gerard said.

"And I explained when we started eight years ago that we did it to save the soccer club and we did it for Adelaide, and I think that was the key.

"... We poured a lot of money into it ... in the end, I believe the job was done.

"Eight years and then someone rang me up, and I suppose then you think 'did you do the job?'. Well, yes, I think it is done well."

Gerard refused to disclose what the European consortium paid for the club but said his fellow SA owners "would all have smiles on their faces, much more than they ever thought was going to happen".