JAKARTA : Indonesia’s trade surplus likely shrank to the lowest in five months in December on slower growth in exports and imports, a Reuters survey showed, although Southeast Asia’s biggest economy is on track to post record exports for all of last year.

The resource-rich country has been riding an export boom on the back of a spike in commodity prices. The December trade data, due to be announced on Monday, is set to confirm that its annual exports reached an all-time high in 2021.

Indonesia has posted a trade surplus every month since May, 2020, boosting the rupiah and helping the currency became one of emerging Asia’s best performers last year.

However, markets are closely monitoring the impact of a coal export ban the government imposed from Jan. 1 to prevent widespread domestic power outages, which economists say could see Indonesia swing back to a trade deficit.

For December, 12 economists in the poll forecast a surplus of $3.13 billion, down from the previous month’s $3.51 billion.

Exports were seen up 40.4per cent on a yearly basis, decelerating from November’s growth pace of 49.7per cent, while imports were expected to rise 39.4per cent, compared with November’s 52.62per cent growth.

Nomura analysts said a full-month coal export ban in January could reduce exports by $4 bilion, which could push Indonesia into a trade deficit. Local brokerage Bahana Sekuritas gave an estimated value of January’s coal exports at around $3 billion.

Authorities in Indonesia this week eased the ban, allowing 37 vessels to depart, although hundreds of miners whose output is estimated to cover up to 40per cent of the country’s total remain barred from exporting.

(Polling by Devayani Sathyan and Tushar Goenka in Bengaluru; Writing by Gayatri Suroyo in Jakarta; Editing by Ed Davies)