Bates, 80, who took control of the club just short of eight years ago, confirmed the first part of the takeover had been completed and he will stay on as chairman until the end of the season to help the new owners during a transitional period.
"We have now completed all the negotiations and investigations with GFH and we've now completed the first part of the purchase and that happened at 10.30pm last night," Bates told Yorkshire Radio.
"Put briefly, they're taking over 100 per cent of the club, as I say the first part was completed at 10.30pm last night and it will be totally completed on December 21.
"Meanwhile there's a transitional period in which they get to know more about the club."
Bates also confirmed that he will be taking on a new role as club president at the end of the season, while one GFH representative, David Haigh, would be joining the club's board immediately, with three more new directors in place before Christmas.
- Sports & Recreation