UK's IG says has discussed handling of franc surge with FCA

* Sector hit by Swiss move to uncap currency in January

* Q3 revenue down 5.1 percent

* Underlying revenue up 7.1 percent (Adds CEO comments, details, share movement)

By Richa Naidu

March 17 (Reuters) - IG Group Holdings has had some discussions with Britain's financial watchdog over how the trading platform handled the Swiss franc's surge on Jan. 15, Chief Executive Officer Tim Howkins said on Tuesday.

"We've had some conversation with them, not a huge amount," Howkins told Reuters as IG Group (Other OTC: IGGHY - news) reported a 5.1 percent decline in third-quarter revenue hurt by the turmoil that followed Switzerland's removal of a cap on its currency.

Underlying revenue, excluding the Swiss franc movement, rose 7.1 percent, driven by growth in active clients.

"(The Financial Conduct Authority) are talking to people across the industry ...I think they're principally interested in understanding how the infrastructure of the market worked," Howkins said.

The FCA and a clients' group said last week that dozens of IG (LSE: IGG.L - news) clients had written to the FCA to complain about how IG handled the Swiss franc's movements in January, which left hundreds with trading losses, including some who said they faced bankruptcy.

IG said it had not been told how many people had directly approached the FCA, which has the power to impose fines and demand redress. Howkins said less than five consumers had made formal complaints to the ombudsman.

"It's very common that if clients suffer a significant loss then their first instinct is to complain," he said.

The FCA, which declined to comment, does not deal with individual complaints but raises issues with companies privately if prompted, for example by a large number of complaints made to the ombudsman.

Britain's financial ombudsman advises people to give companies eight weeks to respond to grievances and gives consumers up to six years after such events to complain.

Shares (Berlin: DI6.BE - news) in IG were down as 0.9 percent as of 1244 GMT on Tuesday. (Additional reporting by Patrick Graham in London; editing by Jason Neely)