* Swiss Exchange plans questionnaire to resolve fee row
* SIX customers have until Nov. 20 to respond
* Chi-X awaiting Swiss decision on new fee
By Luke Jeffs
LONDON, Oct 21 (Reuters) - The Swiss stock exchange plans to poll its largest investment bank clients in an effort to resolve a row with its main trading rivals over its plans to charge them a controversial new fee for using its price data. The Swiss Exchange (SIX) will this week ask its main members, including the world's largest trading banks, whether the stock market should go ahead with the plan, said Werner Buerki, chief executive of SIX's data unit Exfeed.
"We are sending to our trading participants a questionnaire about the proposed fee and, more broadly, the definition of a primary market and reference price," he told Reuters during a trip to London.
SIX said earlier this month it would from Nov. 1 charge rival trading platforms, known as multi-lateral trading facilities (MTFs), an annual fee of 100,000 Swiss francs ($103,800) for using its price data.
SIX planned to levy the new fee on third parties that use price data from the exchange to enable their clients to compare prices on the MTFs with those on the primary exchange.
But the size of the proposed levy dwarfs the fees charged by other European exchanges, brokers say, and has been opposed by MTFs such as investment bank-owned Chi-X Europe, which has asked Britain's Financial Services Authority (FSA) if it could do without taking the SIX price data.
Amid accusations that the Swiss exchange was seeking to take advantage of a dominant position, SIX last week deferred the fee pending "a wider consultation with market participants and regulators to resolve several outstanding matters".
Buerki said: "We have given our customers until Nov. 20 to respond and we will review our plans after that."
Chi-X Europe is waiting for SIX to clarify its final position, according to one source close to the firm.
The MTF said it was keen to promote competition and would participate in any review process. (Editing by Greg Mahlich)