equivalent yield on earning assets decreased to 3.93% for the second quarter of 2020, compared to 4.55% for the first quarter of 2020, and 4.94% for the second quarter of 2019. The decreases in net interest margin and the yield on average earning assets for the second quarter of 2020, compared to the second quarter of 2019, was primarily attributable to a decline in security volumes and interest rate reductions which impacted loans and securities in the second quarter of 2020. The cost of funds on interest bearing liabilities was 0.72% for the second quarter of 2020, 1.17% for the first quarter of 2019, and 1.13% for the second quarter of 2019. The decrease in our cost of funds in the second quarter of 2020 compared to the first quarter of 2020 was primarily driven by the redemption of our junior subordinated debentures and the resulting recognition of $635,000 of deferred issuance costs in March 2020, partially offset by a decline in the volume and rates paid on short-term borrowings. The decrease in our cost of funds in the second quarter of 2020 compared to the second quarter of 2019 was primarily driven by a decline in the rates paid on deposits, a decline in volume and rates paid on short-term borrowings, and the redemption of our junior subordinated debentures in the first quarter of 2020 which resulted in the average yield on our junior subordinated debentures of 4.42% for the second quarter of 2020, compared to 6.47% in the prior year like quarter.
Six months ended June 30, 2020 and 2019
Our net interest and dividend income decreased by $3.4 million to $45.4 million for the six months ended June 30, 2020, compared to $48.8 million for the six months ended June 30, 2019. This decline was attributable to a $5.3 million, or 9.1%, decrease in interest and dividend income for the six months ended June 30, 2020, compared to the six months ended June 30, 2019, partially offset by a $1.9 million decrease in interest expense.
Average earning assets for the six months ended June 30, 2020 were $2.56 billion, reflecting an increase of $120.1 million, or 4.9%, compared to the six months ended June 30, 2019. The yield on average earning assets for the six months ended June 30, 2020 was 4.23%, compared to 4.92% for the six months ended June 30, 2019. Total average loans, including loans held-for-sale, totaled $2.0 billion for the six months ended June 30, 2020, which reflected an increase of $102.3 million, compared to the six months ended June 30, 2019. The growth in average loan balances was more than offset by market interest rate reductions, which resulted in a $3.0 million decrease in interest income for the six months ended June 30, 2020, compared to the like 2019 period. For the six months ended June 30, 2020, yields on average securities decreased by 67 basis points and yields on average loans decreased by 58 basis points, each as compared to the six months ended June 30, 2019, due primarily to the falling interest rate environment. Average interest earning deposits with financial institutions increased $71.8 million in the six months ended June 30, 2020 compared to the prior year like period as consumer spending declined as a result of the COVID-19 pandemic, which increased our liquidity.
Average interest bearing liabilities decreased $71.2 million, or 4.1%, in the six months ended June 30, 2020, compared to the six months ended June 30, 2019. The decrease was due to reductions in average other short-term borrowings of $80.1 million, which primarily consist of FHLBC advances, and a reduction in average junior subordinated debentures of $21.2 million due to the redemption of the trust preferred securities issued by Old Second Capital Trust I and the related $32.6 million of subordinated debentures in March 2020. The rate on our junior subordinated debentures was 9.08% for the six months ended June 30, 2020, and 6.49% for the six months ended June 30, 2019, as $635,000 of deferred issuance costs was expensed upon the redemption in 2020. Average interest bearing deposits increased by $21.3 million in the six months ended June 30, 2020, compared to the six months ended June 30, 2019, but the reduction in market interest rates resulted in a nine basis point reduction in the cost of interest bearing deposits for the six months ended June 30, 2020, compared to the like 2019 period. Average noninterest bearing deposits increased $130.0 million in the six months ended June 30, 2020, compared to the six months ended June 30, 2019, as customers spent less as a result of the COVID-19 pandemic.
Our net interest margin for the six months ended June 30, 2020 was 3.56% compared to 4.03% for the six months ended June 30, 2019, reflecting a 47 basis point decrease. Our net interest margin (TE) for the six months ended June 30, 2020 was 3.62% compared to 4.12% for the six months ended June 30, 2019, reflecting a 50 basis point decrease. The decrease in net interest margin for the six months ended June 30, 2020, compared to the six months ended June 30, 2019, was due primarily to reductions in the market interest rates as well as the issuance of $133.9 million of PPP loans at 1.00%, and the growth of our liquidity with an increase in cash and due from banks, which were not yet reinvested into higher yielding assets. These reductions to the net interest margin were partially offset by reductions in rates paid on deposits, as well as reductions in volumes and rates paid on borrowings, and growth in noninterest bearing deposits, which drove down our overall cost of funds.
We continue to observe competitive pressure to maintain reduced interest rates on loans retained at renewal. While our loan prices are targeted to achieve certain returns on equity, significant competition for commercial and industrial loans as well as commercial real estate loans has put pressure on loan yields, and our stringent underwriting standards limit our ability to make higher-yielding loans.