Money supply in South Korea grew at the lowest pace in four years amid rising expectation for interest rate hike in the foreseeable future, central bank data showed Wednesday.

The M2, called broad money, increased 4.6 percent in August from a year earlier, the lowest increase since August 2013, according to the Bank of Korea (BOK).

The M2 growth continued to slow down from 6.6 percent in April to 5.9 percent in June and 4.6 percent in August.

It came amid widespread expectations that the BOK would hike its policy rate in the near future given that the U.S. Federal Reserve was forecast to raise its benchmark rate of a range of 1.00-1.25 percent further, possibly in December.

The BOK has frozen its policy rate at an all-time low of 1.25 percent since June last year.

The M1, dubbed narrow money, advanced 9.1 percent in August from a year ago.

The M1 refers to currency in circulation, demand deposits and transferable savings deposits equivalent to cash. The M2 adds money market fund, time deposit and financial products that mature in less than two years to M1.