"Euronext considers that the financial terms of a potential competing offer, despite the significant potential synergies, would not be compatible with value creation and adequate return on invested capital for Euronext shareholders," the company said in a statement.

Spain's market regulator CNMV cleared on Thursday a bid by Swiss exchange SIX to buy BME, but left a window for potential rivals to file a counter bid.

(Reporting by Piotr Lipinski in Gdansk; Editing by Susan Fenton)