Tesoro Corp., operator of the largest refinery in Hawaii, said Wednesday its profit rose sixfold in the third quarter as it used more of its refining capacity and increased the profit margin for its products. Net income rose to $345 million, or $2.39 a share, from $56 million, or 39 cents a share, in the year-ago period. San Antonio-based Tesoro used 92 percent of its refining capacity in the quarter, and its earnings were the highest since the second quarter of 2007. Revenue rose 52 percent to $8.1 billion.

The company’s refining margin last quarter at its Campbell Industrial Park facility in Kapolei jumped to $13.58 a barrel from $5 a barrel a year ago. The refining margin is the spread between the cost of crude oil and price of refined products. The Hawaii facility’s yield, or the total number of barrels of refined products of gas, jet fuel, diesel fuel and heavy oils, rose to 76,000 barrels a day from 54,000 barrels a day.