Tesoro Corp., which operates the larger of Hawaii's two oil refineries, said yesterday that its third-quarter profit increased more than fivefold on gains in crude oil purchasing and product pricing.

Net income rose to $259 million, or $1.86 a share in the quarter ending Sept. 30, from $47 million, or 34 cents a share, a year earlier. Results included a one-time accounting gain of 29 cents a share, and a charge of 6 cents for the write-down and other expenses associated with the closure of some retail sites.

Revenue was $8.7 million, up 47 percent, from $5.9 million a year earlier.

“;This quarter's performance highlights our commitment to delivering on our company's stated goal of lowering crude costs and increasing product netbacks,”; Bruce Smith, Tesoro's chief executive, said in a statement.

San Antonio-based Tesoro's refining margin at its Campbell Industrial Park facility rose to $12.15 a barrel versus 32 cents a barrel a year ago. The refining margin is the spread between the cost of crude oil and price of refined products.

The local facility's yield, or the total number of barrels of refined products of gas, jet fuel, diesel fuel and heavy oils, fell to 73,000 barrels a day from 83,000 barrels a day. The total throughput in Hawaii declined to 72,000 from 81,000 barrels a day in 2007.

Tesoro also said yesterday that its board approved a regular quarterly cash dividend of 10 cents a share payable Dec. 15 to shareholders of record as of Dec. 1.