Saudi Arabian Oil Co. and Sumitomo Chemical Co. plan to make a $2 billion loan to Rabigh Refining & Petrochemical Co., as the recent deterioration in the business environment led to a shortfall in working capital at their joint petrochemical business, the Japanese company said Thursday.

Sumitomo Chemical said that it will lend $750 million, or 37.5% of the total financing according to its ownership ratio, and that it will continue to support Petro Rabigh.

Meanwhile, Sumitomo Chemical said it is no longer liable for the loan Petro Rabigh took from banks for its expansion project that the Japanese company previously guaranteed because the project has met certain requirements.

Sumitomo Chemical said it and Saudi Aramco each guaranteed 50% of Petro Rabigh's $5.2 billion in borrowing from a group of banks, including the Japan Bank for International Cooperation, owned by the Japanese government, and the Public Investment Fund, Saudi Arabia's sovereign-wealth fund.