Jean-François Théodore, chief executive of Euronext, on Wednesday promised shareholders in the pan-European stock exchange that any bid for the London Stock Exchange would offer "a very strong return on investment".

He said Euronext’s offer for the LSE, on which it is awaiting a decision by the UK Competition Commission by September 12, had been “well received” by all parties. Euronext has estimated a merger with the LSE would create €203m of annual synergies.