The net interest margin was 4.08% compared to 3.98% for second quarter 2018. The tax equivalency effect on the margin dropped to 0.02% from 0.03% a result of the reduction in tax exempt loans and securities in 2019.
Noninterest income increased 12%, compared to second quarter of 2018, driven by growth in debit card fee income, increases in bank owned life insurance values, gain on sale of loans, and service charges on deposit accounts.
Noninterest expense increased 6% from second quarter 2018. Salary and employee benefit costs increased $197 thousand, or 7%, compared to the prior year quarter, as a result of higher wage and 401k retirement expenses. Professional and director’s fees increased by $69 thousand, or 29%, reflecting higher technology investment to further improve network infrastructure in support of company growth. Marketing and public relations increased by $20 thousand, or 17%, reflecting timing of certain electronic and billboard promotional efforts and the opening of a new banking center. The Company’s second quarter efficiency ratio was 58.0% as compared to 58.4% for the same quarter in the prior year.
Federal income tax expense totaled $613 thousand in second quarter 2019, as compared to $553 thousand tax expense for the same quarter in 2018. The effective tax rate was 19% in both periods.
Average total assets during the quarter amounted to $746 million, an increase of $30 million, or 4%, above the same quarter of the prior year. Average loan balances of $548 million increased $13 million, or 2%, from the prior year second quarter while average securities balances of $111 million decreased $8 million, or 7%, as compared to second quarter 2018.
Average commercial loan balances for the quarter, including commercial real estate, decreased $1 million, or less than 1%, from prior year levels. Average residential mortgage balances including home equity lines of credit increased $12 million, or 7%, over the prior year’s quarter. Average consumer credit balances increased $2 million, or 12%, versus the same quarter of the prior year.
Nonperforming assets increased $156 thousand from June 30, 2018 to $4.6 million, or 0.83%, of total loans plus other real estate at June 30, 2019. The increase in nonperforming assets reflects the second quarter 2019 impairment of a commercial facility in liquidation, partially offset by various commercial loans exiting through liquidation. At June 30, 2019, approximately $1.0 million of thenon-performing loan total is guaranteed by either USDA or the SBA. Delinquent loan balances as of June 30, 2019 declined to 1.03% of total loans as compared to 1.06% at June 30, 2018.
Net loan losses recognized during second quarter 2019 were $35 thousand, or 0.03% annualized, compared to second quarter 2018 net loan losses of $39 thousand. The allowance for loan losses amounted to 1.19% of total loans at June 30, 2019 as compared to 1.11% at June 30, 2018.
Average deposit balances grew on a year over year comparison by $28 million, or 5%, partially on the strength of customer response to higher rates paid on insured deposits. For the second quarter 2019, the average cost of deposits amounted to 0.60%, as compared to 0.38% for the second quarter 2018. During the second quarter 2019, increases in average deposit balances over