Nippon Steel & Sumikin Stainless Corp., Japan"s largest stainless steel producer, increased the price of its nickel-based sheets for a ninth month in September because of higher nickel costs. A tenth rise may follow.

The Tokyo-based company increased the price of its 304- grade steel to 475,000 yen ($4,050) a metric ton this month, from 420,000 yen in August, it said in a statement yesterday. Prices have risen 58 percent this year.

Nippon Steel & Sumikin may charge more for the sheets in October depending on the prices of raw materials, particularly nickel, it said.

Nickel futures have more than doubled this year on the London Metal Exchange, driven by rising demand and falling stockpiles. Nickel is added to steel to make it rust-proof.

Nickel for delivery in three months fell $50, or 0.2 percent, to $27,950 a metric ton at 6:33 p.m. Tokyo time yesterday. The metal traded at $29,950 a ton on Aug. 22, its highest in at least 19 years.

Nippon Steel & Sumikin is 80 percent owned by Nippon Steel Corp. and 20 percent by Sumitomo Metal Industries Ltd., Japan"s third-biggest steelmaker.