Turquoise, the European share trading system that rivals the London Stock Exchange and was founded by nine investment banks, has been put up for sale.

The move is seen as the latest sign that exchanges will have to consolidate, as share trading profit margins become wafer thin.

The LSE is among 18 potential buyers sent details by UBS — which is acting for the owners of Turquoise.

Others receiving the sales data include NYSE Euronext, Nasdaq and Deutsche Börse.

Traditional exchanges face increasing competition from new rivals, with Chi-X the most successful having captured some 20% of the London share trading market.

Turquoise's market share is generally a little more than 5%. Yesterday it captured 7% of the London market, 7.7% of Paris and 5.7% of Frankfurt's share trading.

“There's a sense among our shareholders that we have accomplished their objective of a more efficient and competitive European trading environment,”

Eli Lederman, chief executive of Turquoise, told Bloomberg news.

Turquoise was founded in 2006 by BNP Paribas, Citigroup, Credit Suisse, Deutsche Bank, Goldman Sachs, Merrill Lynch, Morgan Stanley, Société Générale and UBS. It did not begin full trading until September 2008.

Lederman said the business had asked UBS to look at its options. He said he wanted to “continue to develop Turquoise as a business and develop a scenario where we positively influence market structures in Europe”.

The new exchanges, or multi-trading facilities as they are known in the industry, have suffered from launching into a period when share trading volumes have dropped sharply, and conventional stock markets have slashed their costs.

Turquoise remains loss-making and was recently reported to be looking for a third round of financing from its original backers. Their original agreement to make markets in all the stock offered on its platform expired in March.

Earlier this month, new LSE chief executive Xavier Rolet announced he would start looking at new ways of charging clients and further reducing fees, as the Exchange fights to win back some of the 30% or more of market share it has lost to upstarts.