The Office of Fair Trading (OFT) said early investigations showed it had grounds to suspect the BHB might have abused its dominant position but nothing had yet been proven. However, the sport's governing body said it expected to be vindicated by the investigation.
"We remain confident that we will be able to satisfy (the OFT) that we are acting within the provisions of the Competition Act," said Tristram Ricketts, secretary general of the board.
Bookmaker William Hill said the sport's governing body was overcharging Internet betting sites for its lists of runners and riders ahead of race meetings.
"They're hell-bent on using their monopoly to extract an awful lot of money from a downstream activity," William Hill Chief Executive David Harding stated.
The BHB said it would strive to show the OFT it had not infringed competition rules but could face fines of up to 10 per cent of turnover, as well as an order to reform its pricing, if it is found to have broken the rules. William Hill has been involved in a court battle with the board over the right to publish race lists and runners.
British bookmakers Ladbrokes, now part of the Hilton Group, declined to comment on the inquiry and rival high-street betting firm Coral said only that it would be following the case closely.
The British Horseracing Board (BHB) is facing an investigation by the UK's consumer watchdog into allegations it is overcharging online bookmakers for supplying lists of runners and riders at race meetings.
