London extended its lead over New York as the world’s biggest center for currency trading in the six months through October, according to central bank surveys.

Trading grew to an average $1.06 trillion a day in London during October, up 6% from April, and shrank 7.5% in New York to $534 billion in the period, semi-annual surveys conducted by the Bank of England and Federal Reserve showed.

“London has always been the centre of foreign-exchange,” a currency strategist in London at BNP Paribas SA, Ian Stannard, said. “It’s continuing to grow.”

A growing share of the city’s volume is from currencies other than the euro and dollar as eastern Europe economies expand and investors take advantage of Japan’s low interest rates to sell yen and seek higher yields elsewhere. The pound has risen 3% against the yen this year after the BOE lifted rates to 5.25%.

The proportion of London’s trading volume in euros declined by 2 percentage points and in dollars by a percentage point from April. The share in pounds, yen, and other currencies each rose a percentage point in October from April.

“The growth in eastern European markets has been a factor that has helped, as well as the development of markets in Asia,” said Mr. Stannard.