Europe’s antitrust watchdog opened an investigation 22 June into London Stock Exchange Group’s planned $15bn deal to acquire financial data giant Refinitiv, cautioning that the proposed deal could undermine competition.

The European Commission, as expected, expressed concern that bringing together LSE and Refinitiv’s respective trading and clearing activities and financial data products could give the combined entity undue market power. One such area is in the trading of European government bonds, the regulator said.