Interdin is the second Spanish firm with access to the platform, and Turquoise's 17th new member firm of 2012.

Adrian Farnham, CEO at Turquoise, said: "Interdin's membership puts Turquoise in a good position as competition in Spain starts to open up. This is complemented by our price promotion on Spanish equities which has seen good uptake since it began earlier this year.

"A large variety of participants is crucial to ensure liquidity, tight spreads and competitive pricing for investors, and we continue to sign up new members at an encouraging rate."

Jose Luis Diaz-Rio, Managing Director at Interdin, said: "Joining Turquoise is in line with our connection to new alternative venues, and part of the natural evolution of our financial services supported by the latest available technology. Our goal is always to offer our customers the best service, completing our global services with the best execution and greatest possible liquidity."

Turquoise offers lit and dark trading in around 2,000 stocks, depositary receipts and ETFs across 19 countries in Europe and the US. Last year, 106 million trades worth €453.8 billion were carried out on Turquoise's integrated order book, annual increases of 86 per cent and 68 per cent respectively.