Columbia Banking System Inc. is reporting net income of $3.9 million for the second quarter of 2010, compared to a net loss of $6.6 million for the same quarter of 2009.

On a diluted per common share basis, net income for the quarter was 11 cents, compared to a net loss of 37 cents for the second quarter of 2009.

The continuing challenges of the difficult economy resulted in the Tacoma-based bank recording of $13.5 million provision for loan losses for the quarter. In addition, earnings were impacted by one-time conversion expenses because of the Federal Deposit Insurance Corp.-assisted acquisition of the former Columbia River Bank completed during the first quarter of 2010.

The conversion of the former American Marine Bank is scheduled for third quarter 2010.

Net income applicable to common shareholders for the six months ended June 30 was $10.8 million, compared to a net loss of $6.2 million for the first six months of 2009. On a diluted per common share basis, net income for the first six months of 2010 was 34 cents, compared to a loss of 35 cents a year earlier.