Lower fertiliser prices and higher operating costs at Industries Qatar drove down third-quarter net profit at the petrochemicals and metals group by a third, missing analysts forecasts.

The Gulf's second-largest chemical producer by market value after Saudi Arabia's Saudi Basic Industries Co (Sabic), had net profit of 1.73 billion riyals ($475 million) for the three months to end-September, a Reuters calculation based on a nine-month financial statement showed.

This compared to 2.62 billion riyals for the third quarter of 2012.

Analysts polled by Reuters predicted an average of 1.98 billion riyals net profit in the third quarter.

IQ cited a steep decline in fertiliser prices, in line with international trends, and higher operating costs caused by increases in natural gas rates under its supply and purchase agreement with state-owned group Qatar Petroleum.

"Petrochemical prices remain generally weak with most key product prices down on the same period of 2012," the company said.

Revenue for the first nine months of the year was 4.4 billion riyals, a fall of 8.2 percent compared to the same period a year earlier. - Reuters