Interest Income. Interest income increased $2.7 million, or 9.3%, to $32.5 million for the three months ended June 30, 2024 from $29.7 million for the three months ended June 30, 2023. This increase was primarily driven by a 51 basis points increase in the average yield of interest-earning assets which grew from 5.01% during the three months ended June 30, 2023 to 5.52% for the three months ended June 30, 2024 as a result of the higher interest rate environment. During the same comparative period, the average balance of interest-earning assets decreased by $18.5 million, or 0.8%, to $2.4 billion for the three months ended June 30, 2024 as compared to the three months ended June 30, 2023.
Interest income increased $7.5 million, or 13.3%, for the six months ended June 30, 2024 reaching $63.6 million from $56.1 million for the six months ended June 30, 2023. This increase was driven by a $47.9 million increase in the balance of average interest-earning assets between the two periods. Within the average balance of interest-earning assets, the average balance of loans receivable (net of PPP loans) grew $78.9 million, or 4.8%, between the six months ended June 30, 2024 and June 30, 2023. In addition, the average yield of interest-earning assets increased by 51 basis points from 4.87% for the six months ended June 30, 2023 to 5.38% for the six months ended June 30, 2024 as a result of the higher interest rate environment.
Interest income on loans increased by $2.9 million, or 12.2%, to $26.8 million during the three months ended June 30, 2024 from $23.9 million during the three months ended June 30, 2023. The increase in interest income on loans was primarily due to the increase in the average balance of loans (net of PPP loans) and an increase in the average yield on loans. The average balance of these loans increased by $39.1 million, or 2.3%, to $1.7 billion for the three months ended June 30, 2024 compared to the three months ended June 30, 2023. The increase in the average balance of loans was due to stability in commercial real estate loan balances, including commercial real estate construction, as well as growth in our commercial and industrial loan portfolio. The average yield on loans, excluding PPP loans, increased by 54 basis points to 6.21% for the three months ended June 30, 2024 from 5.67% for the three months ended June 30, 2023 as a result of the extended higher interest rate environment and management’s continued focus on disciplined loan pricing.
For the six months ended June 30, 2024, interest income on loans increased by $6.7 million, or 14.6%, reaching $52.4 million as compared to $45.7 million for the six months ended June 30, 2023. The increase in interest income on loans represents the impact of growth in average loan balances (net of PPP loans) of $78.9 million between the six months ended June 30, 2023 and June 30, 2024. The increase in average loans outstanding was due to an increase in the commercial and industrial segment of the loan portfolio as well as stability in commercial real estate loan balances, including commercial real estate construction. This increase in production was also coupled with an increase in average yield on loans, excluding PPP loans, for the six month periods from 5.57% in 2023 to 6.06% in 2024. The increase in the average yield on loans was driven by the effect of the higher interest rate environment during 2023 and the first half of 2024 and management’s continued focus on disciplined loan pricing.
Interest income on securities decreased by $178 thousand to $3.4 million during the three months ended June 30, 2024 from $3.5 million during the three months ended June 30, 2023. The decrease in interest income on securities was driven primarily by a decrease in the average balance of securities outstanding during the current period due to certain maturities as well as a result of the Signature Bank subordinated debt writeoff during 2023. The average balance of securities decreased by $48.5 million, or 9.4%, to $467.3 million for the three months ended June 30, 2024 compared to $515.9 million for the three months ended June 30, 2023. The average yield on investment securities increased by 14 basis points overall from 2.75% for the three months ended June 30, 2023 to 2.89% for the three months ended June 30, 2024. The increase in the average yield reflected the continued maturity of lower yielding investments during the current period.
For the six months ended June 30, 2024, interest income on securities decreased by $313 thousand, or 4.4%, to $6.8 million during the period from $7.1 million during the six months ended June 30, 2023. The decrease in interest income on securities was due to a decrease in the average balance of securities during the current period. The average balance of securities decreased by $48.8 million, or 9.3%, to $474.4 million for the six months ended June 30, 2024 compared to $523.3 million for the six months ended June 30, 2023 due to certain maturities as well as a result of the Signature Bank subordinated debt writeoff during 2023. The average yield on investment securities increased by 13 basis points overall from 2.74% for the six months ended June 30, 2023 to 2.87% for the six months ended June 30, 2024. The increase in the average yield on securities was primarily related to the maturity of lower yielding securities during 2023 and the first half of 2024.