Japan's Idemitsu Kosan Co. Ltd.'s net income attributable to shareholders spiked 117% on the year to more than ¥55 million during the first quarter of fiscal year 2018, which spans April 1 through June 30.

The company's operating income during the period was ¥71.5 million, rising more than 106% from the same period a year earlier, due mainly to higher margins on petroleum products and the positive effect of inventory valuation, according to an Aug. 14 news release.

Additionally, total net sales improved during the period, coming in at more than ¥1 billion, rising 20.8% on the year.

As of Aug. 13, US$1 was equivalent to ¥110.71.