* Q3 net profit 2.56 bln riyals vs 2.07 bln - Reuters calculations
* Results beat average analysts forecasts
* 9-mth net profit 6.6 bln riyals vs 6.2 bln riyals
DOHA, Oct 14 (Reuters) - Petrochemicals and metals company Industries Qatar (IQ) posted a 23.7-percent jump in third-quarter net profit on Sunday, Reuters calculations show, beating average analysts' forecasts.
The Gulf's second-largest chemical producer by market value behind Saudi Basic Industries (SABIC) made a net profit of 2.56 billion riyals ($703.2 million) for the third-quarter, according to Reuters calculations, compared with 2.07 billion riyals a year earlier.
Analysts polled by Reuters on average expected the company to post quarterly profit of 2.2 billion riyals.
The company did not provide third-quarter numbers in a bourse statement. Reuters calculated the profit figure for the third quarter from past financial statement.
IQ made a nine-month net profit of 6.6 billion riyals compared to 6.2 billion riyals a year ago, a company statement said without giving further detail.
In August the company posted a first-half net profit of 4.04 billion riyals.
Petrochemical prices have strengthened in recent months, but worries persist over the impact of a global slowdown on industry earnings in the world's top oil exporting region.
In February, IQ inaugurated Qafco 5, a 1 million tonne urea facility while Qatar Petrochemical Co (QAPCO) - which is 80-percent owned by Industries Qatar and 20 percent held by France's Total - began operating its polyethylene 3 plant during the second quarter.
Qatar has embarked on a massive domestic building programme in preparation to host the 2022 World Cup soccer tournament, with plans to spend $11 billion on a new international airport, $5.5 billion on a deepwater seaport and $1 billion for a transport corridor in the capital, Doha.
In April IQ said the steel segment was expected to "significantly benefit from the progressive and wide-ranging infrastructure plans of the State of Qatar".
IQ shares were trading up 1.5 percent on the Doha bourse Sunday at 0705 GMT. ($1=3.638 Qatari riyals) (Reporting By Regan Doherty, Editing by Dinesh Nair)