KUALA LUMPUR, Jan 28 — Malaysia’s ringgit dropped the most in a week after Singapore unexpectedly loosened monetary policy, joining a global round of easing amid slowing economic growth and the risk of deflation.

The Singapore dollar fell as much as 1.3 per cent against the greenback, the biggest loss since 2010, as the central bank said today it will reduce the slope of its currency band while sticking with a modest and gradual appreciation.

Malaysia’s monetary authority meets today and the consensus in a Bloomberg survey is for no change.

“The ringgit is weakening because of the surprise move by the Monetary Authority of Singapore,” said Jonathan Cavenagh, a foreign-exchange strategist at Westpac Banking Corp in Singapore. “That’s the main driver.”

The ringgit depreciated 0.6 per cent to 3.6185 a dollar in Kuala Lumpur, data compiled by Bloomberg show. The currency slid to 3.6277 on January 21, the weakest level since April 2009.

A plunge in oil prices has made the ringgit Asia’s worst-performing currency in the past three months with a 9.5 per cent loss. The nation is the region’s only major exporter of the fuel. Cavenagh predicts the ringgit will retreat to 3.65 a dollar in the next few months.

Malaysia will keep its benchmark overnight policy rate at 3.25 per cent, according to all 19 economists surveyed by Bloomberg before the 6pm decision local time. Thailand’s central bank held its key rate at 2 per cent today.

The yield on the nation’s 10-year sovereign bonds dropped six basis points, or 0.06 per centage point, to an eight-week low of 3.86 per cent, data compiled by Bloomberg show. — Bloomberg