Saudi Arabian Oil Co. offered naphtha supplies in the first half of 2013 at premiums that are as much as $7 a metric ton more than those in the second half of 2012, said three people with knowledge of discussions with buyers.

The company known as Saudi Aramco yesterday offered A-310 naphtha at a premium of $36 a metric ton to its benchmark formula, the people said, asking not to be identified because the discussions are confidential. Rabigh and Jeddah grades were at premiums of $32 a ton, while Al-Jubail was offered at $33 and A-180 grade at $30, they said.

Nobody answered a telephone call and two e-mails to the company’s media relations department in Dhahran.

For the second half of 2012, Saudi Aramco set premiums for A-310 at $33 a ton, Al-Jubail at $29 and A-180 grade at $31, according to data compiled by Bloomberg. Rabigh and Jeddah grades were sold at $25 a ton.

To contact the reporter on this story: Ann Koh in Singapore at akoh15@bloomberg.net

To contact the editor responsible for this story: Alexander Kwiatkowski at akwiatkowsk2@bloomberg.net