Canada's biggest securities regulator on Thursday ruled that Omega Securities could continue to run its two alternative trading systems ahead of a hearing on whether it is operating in breach of Ontario provincial law.

A three-person panel of the Ontario Securities Commission (OSC) denied a request from its own enforcement staff that Omega halt trading operations while the OSC reviews the matter.

The enforcement staff have said they discovered that notification of some trades processed by Omega are sent with different time stamps, raising concerns that some parties are getting early access to the information.

Securities rules require that trade data cannot be released to any individual organizations before it is disseminated to the public.

Omega Chief Executive Sean Debotte declined to comment on the panel's ruling.

An Omega attorney told the panel on Tuesday that the company had not broken the law.

The panel ordered Omega to inform its subscribers that time stamps on trades they receive might differ by milliseconds from data disclosed to the public. It also ordered the firm to address the discrepancies as quickly as possible.

Omega said during the hearing that trading volumes on its two markets had fallen by about 90 per cent since the case became public last week. Those markets process about five per cent of all Canadian equities trades in a typical month, according to a national self-regulatory organization.