Japan's current account surplus, the broadest measure of trade, expanded 8.8 percent in the first half of this year from a year earlier, due to a shrinking deficit in services, the Finance Ministry said Thursday.

The surplus in the current account -- which measures not only trade but investment flows and cash transfers -- grew to 6.73 trillion yen, despite the shrinking surplus in merchandise trade, according to the preliminary report.

Factors such as the recovering economy, the yen's appreciation against the dollar and higher oil prices remain unchanged and are behind the shrinking trend of the goods-trade surplus, the main ingredient of the current account, a ministry official said.

For June alone, the current account surplus was down 5.5 percent from a year earlier to 1.31 trillion yen as recovering firms paid increased share dividends to foreign investors. The surplus in merchandise trade alone edged up 1.4 percent in the month.

In the January-June period, the surplus in merchandise trade -- exports minus imports -- slipped 5.2 percent to 6.56 trillion yen. Imports, such as crude oil, expanded 14.8 percent, outpacing exports, such as semiconductors, which grew 8.6 percent.

The surge in imports was attributed to recovering domestic demand and higher oil prices. The average yen-based oil price in the six-month period was 82.6 percent higher from a year earlier.

The service deficit came to 2.45 trillion yen, down 480.4 billion yen, because of the yen's appreciation.

Fee income on Japanese stocks bought by foreign investors rose while administrative cost payments by Japanese firms located abroad declined.

The yen averaged 106.84 to the dollar in the period, compared with 118.81 in the corresponding period last year.

As a result, the trade surplus in goods and service trade combined grew 3.1 percent to 4.11 trillion yen.