SNB purchased 86.1 bln Sfr in foreign currency in 2015 to weaken franc

ZURICH, March 24 (Reuters) - The Swiss National Bank (SNB) purchased 86.1 billion Swiss francs in foreign currency last year to enforce the minimum exchange rate, lifted in January, and influence exchange rate developments, according to its annual report published on Thursday.

The SNB said that aside from purchasing foreign currency, it did not conduct any monetary policy-related open market operations last year.

Currency intervention along and currently negative interest rates are the SNB's main tools to protect Switzerland's export-oriented economy from the effects of too strong an appreciation of the franc. (Reporting by Silke Koltrowitz and Joshua Franklin; Editing by Simon Cameron-Moore)