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ZURICH, Nov 23 (Reuters) - The Swiss central bank stands ready to intervene should an Italian referendum on constitutional reform next month unleash turmoil on currency markets, Swiss National Bank governing board member Andrea Maechler said on Wednesday.
Italy is due to vote on the reforms on Dec. 4, an event which could trigger uncertainty and a rush into the safe-haven Swiss franc, pushing it higher against the euro.
The SNB entered the market to weaken the franc in the wake of Britain's vote to quit the European Union, while recent data suggested it was selling francs after the U.S. election.
"We went through two quite horrid nights with Brexit and the U.S. elections," Maechler said at the CFO Forum event in Zurich.
"We will have to clearly monitor what the developments are (with regard the Italian election) and we stand ready to react as needed in the best possible way from a Swiss monetary policy perspective."
Maechler defended the SNB's use of negative interest rates and currency market interventions to rein in the franc, which she said remained "clearly overvalued."
"The development of the exchange rate has shown that our twin-pillar approach is successful and has reduced the overvaluation pressure on the franc," Maechler added.
"Without negative interest rates the franc would be stronger, industry would be damaged and inflation would be lower."
At every monetary policy assessment the SNB considered the costs and benefits of potentially lowering the negative rates from their current level of - 0.75 percent, she said.
But she indicated there could be limits to the policy, which has come under fire from banks.
"We have interest rates at a record low. We don't have much leeway," Maechler said, adding the SNB would examine how rates were passed on to ordinary savers.
So far most banks have held off passing on the negative rates to ordinary customers, although some, such as PostFinance , have moved to charge wealthy clients a fee for holding larger deposits. (Reporting by John Revill; Editing by Michael Shields)