UPDATE 1-Turquoise hires UBS to seek a buyer

* CEO says shareholders have achieved what they wanted

* Investors in trading platform happy to cede control -CEO

(Adds CEO comments)

LONDON, Aug 18 (Reuters) - Turquoise, the pan-European equity trading venture backed by nine of the world's biggest investment banks, hired UBS AG (UBSN.VX) to develop options for its future including seeking potential buyers.

Turquoise Chief Executive Eli Lederman said on Tuesday shareholders had done what they wanted in catalyzing competition in Europe and were ready to move on to the next stage.

"They're now happy to cede control to someone -- if the right party or parties appear -- to back Turquoise's next steps as a positive influence on European market structure," Lederman told Reuters.

Sales documents have been send to all major exchanges and so-called multilateral trading facilities (MTFs), including the London Stock Exchange (LSE.L), Deutsche Boerse (DB1Gn.DE), Nasdaq OMX (NDAQ.O), NYSE Euronext (NYX.N)(NYX.PA), SIX and Chi-X, according to people familiar with the matter.

UBS was appointed a couple of months ago to explore all strategic options, one of the sources said.

The move comes as MTFs, or start-up alternative trading platforms, face increasing financial pressure as trading volumes decline. European trading operators have been saying it was impossible for MTFs to break even and expect consolidation across the industry.

Turquoise, which told Reuters in May it was considering a third round of fundraising, is backed by Citi (C.N), Goldman Sachs (GS.N), Bank of America Merrill Lynch (BAC.N), Morgan Stanley (MS.N), UBS, Credit Suisse (CSGN.VX), Deutsche Bank (DBKGn.DE), BNP Paribas (BNPP.PA) and Societe Generale (SOGN.PA).

The trading platform, launched in August 2008, is still loss-making but has about a 7 percent market share. (Reporting by Daisy Ku; Editing by Dan Lalor and David Holmes)