July 6 (Bloomberg) -- National Iranian Oil Co. is poised to increase the official selling price for its main Iranian Light crude oil to Asia in August to the highest in 13 months after Saudi Arabia raised prices yesterday.

Iran’s state-owned oil company will set Iranian Light at a premium of $1.84 a barrel to the average of Persian Gulf benchmarks Oman and Dubai grades, according to Bloomberg calculations. That’s up 10 cents, or 5.7 percent, from July’s premium, based on a quarterly formula tied to prices set by Saudi Arabian Oil Co.

Saudi Aramco, as state-owned Saudi Arabian Oil is known, raised the price for Arabian Light crude for August shipments to Asia by 10 cents a barrel yesterday on refinery demand for high- sulfur cargoes valued for their fuel-oil yield. Asian refiners had anticipated a price cut for light grades from Saudi Arabia, according to a Bloomberg survey last week.

National Iranian Oil’s Iranian Heavy and Forozan Blend grades, linked to Saudi Aramco’s Arabian Medium crude, will be reduced by 30 cents a barrel to discounts of 38 cents and 43 cents to the Oman-Dubai average, respectively, according to the formula. Saudi Aramco yesterday cut Arabian Medium by 30 cents a barrel, dropping the grade’s premium to the Oman-Dubai average by half.

National Iranian will formally announce its prices for the three grades to be supplied to Asia, the Mediterranean, Northwest Europe and South Africa later this week. It will also set August prices for Soroush and Norooz, which are shipped only to Asia and the Mediterranean.

Iran, the second-largest producer in the Organization of Petroleum Exporting Countries, pumped 3.75 million barrels a day last month, more than its quota of 3.34 million, according to a Bloomberg survey of analysts and producers.

To contact the reporter on this story: Yee Kai Pin in Singapore at kyee13@bloomberg.net

Last Updated: July 5, 2009 21:39 EDT