Investment securities totaled $984.9 million, or 19.1% of total assets at September 30, 2020, versus $640.8 million, or 18.4% of total assets at September 30, 2019. The average balance of investment securities increased $335.8 million in prior year quarterly comparison, mostly as a result of the acquisitions of FFB and SWG. The average tax equivalent yield on investment securities decreased 76 basis points to 2.48% from 3.24% in prior year quarterly comparison. The investment portfolio had a net unrealized gain of $33.2 million at September 30, 2020 as compared to a net unrealized gain of $13.9 million at September 30, 2019.
The FTE average yield on all earning assets, a non-GAAP measure, decreased 80 basis points in prior year quarterly comparison, from 4.94% for the third quarter of 2019 to 4.14% for the third quarter of 2020. Average interest expense decreased 56 basis points from 1.17% for the third quarter of 2019 to 0.61% for the third quarter of 2020. Cost of all deposits averaged 47 basis points for the third quarter of 2020 compared to 76 basis points for the third quarter of 2019. See reconciliation of non-GAAP financial measures provided below.
First nine months 2020 compared to first nine months 2019
The Company reported net income available to common shareholders of $37.2 million for the nine months ended September 30, 2020, compared to $31.9 million for the same period last year. Operating net earnings decreased $2.6 million, or 7.4%, from $34.8 million at September 30, 2019 to $32.2 million at September 30, 2020. Provision for loan losses increased $18.7 million for the year-over-year comparison. Operating net earnings excludes merger-related costs of $2.5 million, net of tax, $7.0 million bargain purchase gain and a gain on the sale of land of $463 thousand, net of tax, for the year-to-date period ending September 30, 2020, and merger-related costs of $3.1 million, net of tax, and income of $174 thousand, net of tax, related to the Financial Assistance Award from the U.S. Department of the Treasury, for the year-to-date period ending September 30, 2019. Operating earnings per share were $1.56 on a fully diluted basis for nine-month period ending September 30, 2020, compared to $2.07 for the same period in 2019, excluding the merger-related costs and income described above. See reconciliation of non-GAAP financial measures provided below.
Net interest income increased to $113.2 million, or 28.1%, for the nine months ended September 30, 2020, compared to $88.4 million for the same period in 2019. This increase was primarily due to interest earned on a high volume of loans and securities. Average earning assets at September 30, 2020, increased $1.086 billion, or 35.5%, and average interest-bearing liabilities increased $1.446 billion, or 61.7%, when compared to December 31, 2019.
Non-interest income for the nine months ended September 30, 2020, was $30.9 million compared to $19.4 million for the same period in 2019, reflecting an increase of $11.6 million or 59.7%. Excluding the awards and gains mentioned above, non-interest income increased $4.2 million in year-over-year comparison. Mortgage income increased $2.9 million and interchange fee income increased $923 thousand in the year-over-year comparison.
The provision for loan losses was $21.6 million for the nine months ended September 30, 2020, compared with $2.9 million for the same period in 2019. The allowance for loan losses of $34.3 million at September 30, 2020 (approximately 1.09% of total loans) is considered by management to be adequate to cover losses inherent in the loan portfolio. Total valuation accounting adjustments totaled $8.8 million on acquired loans. See “Allowance for Loan and Lease Losses” in Item 2. – Management’s Discussion and Analysis of Financial Condition and Results of Operations for more information on this evaluation.
Non-interest expense was $78.4 million for the nine months ended September 30, 2020, an increase of $14.8 million or 23.3%, when compared with the same period in 2019. $11.7 million of the increase is related to the operations of FFB and SWG.
FINANCIAL CONDITION
The First represents the primary asset of the Company. The First reported total assets of $5.155 billion at September 30, 2020 compared to $3.935 billion at December 31, 2019, an increase of $1.220 billion. Loans increased $546.9 million to $3.144 billion, or 21.1%, during the first nine months of 2020. Deposits at September 30, 2020 totaled $4.306 billion compared to $3.082 billion at December 31, 2019.
For the nine months period ended September 30, 2020, The First reported net income of $43.0 million compared to $37.3 million for the nine months ended September 30, 2019. Merger charges, net of tax, equaled $2.1 million for the first nine months of 2020 as compared to $3.1 million for the first nine months of 2019.