TRADE : Japan’s Current Account Surplus Jumps : Commerce: May figure hits $8.94 billion. Analysts see strong yen continuing to inflate value of exports.

Japan’s current account surplus, its broadest measure of trade in goods and services, shot up to $8.94 billion in May from $8.34 billion a year earlier, the Finance Ministry reported Thursday.

Economists said they expect a bumpy ride before a decisive falling trend in the surplus is established.

The “J-curve effect,” in which yen appreciation temporarily inflates the value of merchandise exports in dollar terms, could persist for some time, they said.

Brisk growth in imports and a rise in the deficit in services such as travel are the only two factors that can restrain growth of the surplus for now, economists said.

“It’s a tug of war between growth in merchandise export surpluses inflated by the yen’s rise and the brisk growth of imports,” a senior economist at Bank of Tokyo said.

“But problems mainly lie in exports, whose value has swelled because of the yen’s rapid rise,” he said.

The Finance Ministry said the merchandise trade surplus rose to $10.01 billion in May from a revised $8.75 billion a year earlier, but it was down from $12.47 billion in April.

Exports jumped to $34.35 billion in May from $27.39 billion a year earlier, but imports grew even faster in percentage terms, rising to $24.34 billion from $18.64 billion.

A ministry official told reporters that the current account surplus is on a shrinking trend and that the dollar-denominated surplus rose in May because of a special factor and the yen’s strength.

Economists said manufacturers’ attempts to raise sales prices abroad, in a bid to avoid losses on yen earnings because of the dollar’s decline, had also accelerated increases in export values.

“Rises in export values and prices may soon hit their peaks, but the overall surplus could remain higher than a year ago for the next few months because of the yen’s rise,” said Kenji Yumoto, a senior economist at Japan Research Institute.

The dollar has stayed in the range of 82 to 88 yen in recent months after hitting a record low of 79.75 in April. It was valued at about 96 to 105 yen during the latter half of last year.

The strong yen has forced Japanese companies to shift more production overseas, particularly within Asia, as an alternative to exporting, and to increase overseas procurement.

However, those companies’ efforts have also increased exports of equipment and parts necessary for overseas operations, slowing the pace of decline in the trade surplus, economists said.

On the other hand, imports have grown much faster than exports, and Japan Research’s Yumoto said he expects imports to continue growing at double-digit rates for now.

In tandem with the U.S.-Japan car trade accord reached last week, Japan’s top auto makers unveiled plans to boost output in North America and other countries and to increase purchases of foreign parts.

Some economists said it will take time to see the effect of these plans on the trade surplus but that it might become visible later this year.