the six months ended June 30, 2019. The average balance of investment securities decreased $1.4 million, or 21.0%, to $5.2 million for the six months ended June 30, 2020 from $6.6 million for the six months ended June 30, 2019, while the average yield on investment securities decreased 56 basis points to 1.80% for the six months ended June 30, 2020 from 2.36% for the six months ended June 30, 2019. The average balance of other interest-earning assets increased $11.9 million, or 350.4%, to $15.3 million for the six months ended June 30, 2020 from $3.4 million for the six months ended June 30, 2019, and the average yield on other interest-earning assets decreased 129 basis points to 0.82% for the six months ended June 30, 2020 from 2.11% for the six months ended June 30, 2019.
Interest Expense. Total interest expense decreased $93,000, or 9.7%, to $870,000 for the six months ended June 30, 2020 from $963,000 for the six months ended June 30, 2019. The decrease was due to a decreases of $58,000 or 9.5% in interest expense on deposits and $35,000, or 9.9%, in interest expense on advances from FHLB. The average balance of interest-bearing deposits in banks decreased $1.7 million, or 2.8%, to $57.3 million for the six months ended June 30, 2020 from $59.0 million for the six months ended June 30, 2019, and the average cost of interest-bearing deposits in banks decreased 14 basis points to 1.93% for the six months ended June 30, 2020 from 2.07% for the six months ended June 30, 2019. The average balance of FHLB advances decreased $1.9 million, or 8.0%, to $22.1 million for the six months ended June 30, 2020 from $24.0 million for the six months ended June 30, 2019. The average cost of these advances decreased six basis points to 2.87% for the six months ended June 30, 2020 from 2.93% for the six months ended June 30, 2019.
Net Interest Income. Net interest income decreased $141,000, or 15.5%, to $766,000 for the six months ended June 30, 2020 from $907,000 for the six months ended June 30, 2019. Average net interest-earning assets increased $7.5 million period to period. This increase was due primarily to an increase in the average balance of interest-bearing deposits in banks period to period. The increase in interest-bearing deposits in banks was principally due to funds received in the stock offering. Our interest rate spread decreased to 1.13% for the six months ended June 30, 2020 from 1.79% for the six months ended June 30, 2019, and our net interest margin decreased to 1.56% for the six months ended June 30, 2020 from 2.00% for the six months ended June 30, 2019. The decreases in interest rate spread and net interest margin were primarily the result of lower interest rates on the increased balance of interest-bearing deposits in banks due to the funds received in the stock conversion not yet utilized to fund loans and the sharp decrease in market interest rates since June 30, 2019.
Provision for Loan Losses. There was no provision for loan losses for the six months ended June 30, 2020 compared to a benefit of $9,000 for the six months ended June 30, 2019. The allowance for loan losses was $850,000, or 1.20% of total loans, at June 30, 2020, compared to $850,000, or 1.08% of total loans, at December 31, 2019, and $850,000, or 1.08% of total loans, at June 30, 2019. Classified (substandard, doubtful and loss) loans decreased to $564,000 at June 30, 2020 from $567,000 at December 31, 2019 and $578,000 at June 30, 2019. There were no non-performing loans at June 30, 2020, December 31, 2019 or June 30, 2019. There were no charge-offs or recoveries for the six months ended June 30, 2020. There were net recoveries of $9,000 for the six months ended June 30, 2019.
Noninterest Income. Noninterest income increased $156,000, or 59.5%, to $418,000 for the six months ended June 30, 2020 from $262,000 for the six months ended June 30, 2019. The increase was primarily due to an increase of $166,000 in fees on loans sold, offset in part by a decrease in service charges and other income of $10,000.
Noninterest Expense. Noninterest expense increased $183,000, or 16.5%, to $1.3 million for the six months ended June 30, 2020 from $1.1 million for the six months ended June 30, 2019. There was an increase of $116,000, or 16.9%, in salaries and employee benefits. The increase resulted primarily from an increase of $76,000 in commissions paid on higher loan volume period to period and $41,000 of expenses recognized for the employee stock ownership plan. There were also increases of $61,000, or 127.1%, in accounting and consulting expense and $31,000, or 3,100.0%, in legal expense due to increased costs of operating as a public company, as well as increases of $4,000, or 10.8%, in insurance expenses and $12,000, or 11.8%, in other expense. These increases were offset in part by decreases of $33,000, or 24.4%, in occupancy expense, $4,000, or 11.1%, in FDIC deposit insurance premiums due to a “small bank” assessment credit issued by the FDIC in late 2019 and $4,000, or 6.7%, in data processing expense.
We expect our noninterest expense to increase in future periods because of the anticipated costs associated with operating as a public company, including the expected hiring of additional accounting personnel, and the increased