Hawaiian Electric Industries Inc.’s earnings edged lower in the third quarter as a decline in net income at its bank subsidiary more than offset a modest gain in its utility business.

HEI earned $47.7 million, or 49 cents a share in the July-through-September quarter, down from $48.4 million, or 50 cents a share during the same period a year earlier, the company reported today.

Hawaiian Electric Co. and affiliates Maui Electric Co. and Hawaii Electric Light Co. earned a combined $38.4 million in the third quarter, up from the $38 million they earned during the third quarter of 2011.

Today’s financial report included results for American Savings Bank that HEI originally reported last week. American Savings earned $14.2 million in the third quarter compared with $15.5 million in the year-earlier period.

“HEI had another solid quarter as we continued to invest in our Hawaii businesses,” said Constance Lau, the company’s president and chief executive officer.

Lau note that HECO’s relatively flat performance in the third quarter was the result of its recovery of costs for reliability and clean energy being largely offset by higher operations and maintenance expenses.

So far this year HECO has invested $188 million — roughly twice its earnings — in projects to modernize its grid and integrate increasing amounts of alternative energy, Lau said.

HEI shares closed down 58 cents at $25.10 today on the New York Stock Exchange.