ZURICH (Reuters) - The Swiss National Bank (SNB) went on its biggest foreign-currency buying spree since January 2015 in the wake of Britain's vote to leave the European Union, data showed on Monday.
Commercial and other deposits with the SNB rose to 507.514 billion Swiss francs ($520.69 billion) from 501.231 billion the previous week, indicating the bank had bought foreign exchange on the market and then credited depositors' accounts.
The bank is using negative rates, coupled with an unspecified amount of foreign currency purchases, to weaken the franc and protect exports to the euro zone, Switzerland's biggest trading partner.
"Brexit has triggered a big demand for safe havens like the franc, so the SNB has to keep acting," J. Safra Sarasin currency strategist Ursina Kubli said.
Switzerland's central bank gave rare confirmation it was intervening to halt appreciation of the franc within hours of Britain's referendum becoming clear on June 24.
Analysts said that its unusual step of making its intentions clear was intended to maximise the impact of intervention.
The SNB declined to comment on its future strategy to limit the franc's strength.
Swiss manufacturers have struggled with the currency's strength which reduces their profitability.
"If the franc went back to 1.10 versus the euro, it would be a significant relief," Hans Hess, president of manufacturers' lobby Swissmem, said.
On Monday the franc traded at about 1.08 per euro (EURCHF=).
($1 = 0.9747 Swiss francs)