SEOUL - Hyundai Motor, South Korea's top carmaker, logged an 8.8 percent decline in its third-quarter operating profit, a regulatory filing showed Thursday.

Operating profit reached 1.50 trillion won ($1.33 billion) in the three months ending Sept 30, down 8.8 percent from a year earlier.

Revenue increased 10.1 percent from a year earlier to 23.43 trillion won in the third quarter, but net income sank 25.3 percent to 1.21 trillion won.

Despite strong auto sales, a rise in marketing costs and a volatility in the foreign exchange market resulted in the worse-than-expected earnings.

Market expectations for the operating profit had been set at 1.59 trillion won for the third quarter.