The Toronto Real Estate Board is threatening real estate companies it says are "jumping the gun" by releasing Greater Toronto Area home sales data from unknown sources before the board has permitted it.

The board sent cease-and-desist letters, warning it will take away data access and TREB memberships or bring legal action against members it believes are violating its user agreement by posting sale numbers online "in an open and unrestricted fashion."

The board's lawyer Brian Facey said in an email to The Canadian Press on Thursday that the letters are an attempt to find out the source of the members' numbers and "ensure no one has breached their contracts with TREB."

The data has been a contentious issue for TREB ever since the Competition Bureau began pushing to allow realtors to post it through password protected webpages called virtual office websites seven years ago, saying it impedes competition and digital innovation.

Citing privacy and copyright concerns, TREB fought its release for seven years at three different judicial bodies, but lost every time.

Its latest blow came in August when the Supreme Court of Canada refused to hear the case. TREB then said it would permit its members to publish the data after the board takes 60 days to prepare for its release and make it available to members — an allowance given to the board by the Competition Tribunal years ago when the case was studied at the quasi-judicial body.

The Competition Bureau believes the 60 days passed in between TREB's appeals to various courts, but TREB claims the clock has yet to run out.

"TREB has not gone 'live' yet, but is trying to do so by mid-September to comply with the Order early to allow all members to be on a level playing field as soon as possible," said Facey.

"If a member has been posting sold data at the current time, TREB does not know the source of this information."

Toronto realtor David Fleming says no one really knows why the source of the information is so important for TREB, but it could be of value to the board because it is trying to find out if these data sources are out of their jurisdiction.

"If TREB is sending threatening letters to its membership, it seems to reason that they would probably like to send the same threatening letter to people who are providing the data," he said, noting that it is also a possibility that TREB is looking to determine sources so it can create a meaningful partnership with them.

Members, he said, are already lamenting that the fight could continue.

"I feel we have not seen the last of this," he said.

In late August, Facey said the board was still considering whether to fight for adjustments to an order allowing the data's online publication.

On Tuesday, TREB refused to say how many letters it has sent to members it believes are violating orders, saying "TREB does not find it productive to publicly discuss the details of internal matters, and/or matters that can/may end up before the courts."

A copy of the letter obtained by The Canadian Press shows TREB is threatening recipients that violators could "lose access to the data, have their membership in TREB revoked or face further legal action in the courts," if they don't comply with TREB's terms.

Zoocasa chief executive officer Lauren Haw confirmed her real estate website received a letter. She said her company first posted the data without password protections because of a "technical issue," but immediately corrected the mistake and installed password protections.

TREB has yet to respond to a request from her seeking clarity around how data can be posted, she added.

"I am just disappointed we are now in a state of grey," she said. "I am now, as a business operator, afraid of my own membership body based on threatening legal letters..., which is the definition of, I think, anti-competitiveness."

Joseph Zeng of HouseSigma Inc. also received a letter after his real estate company released the information. He hired a lawyer to communicate with TREB to clarify how the company can release data without violating TREB rules.

"We are very confused," he said. "When we received the letter, me and my team were really puzzled about what exactly TREB is trying to do."