To boost the transparency of dark trading, the TMX Group is planning to start tagging dark trades on all of its market data feeds.

The exchange announced it will add the tag “isDark” to its data feeds for both the Toronto Stock Exchange (TSX) and the TSX Venture Exchange. The new tag is slated to be implemented in the third quarter, it says.

By singling out dark trades, the TSX says market watchers will be able to “easily quantify the size of TSX dark trading,” which will enhance the transparency of this type of trading activity.

The new tag will be introduced to the exchange’s testing environment on May 17. The exact date for its implementation will be announced in a future notice.