Income from interest-bearing due from banks totaled $74,000 in 2021, an increase of $33,000 (80.5%) from $41,000 in 2020. The average yield on interest-bearing due from banks decreased to 0.16% in 2021 from 0.44% in 2020, consistent with the decrease in market rates. The average balance increased $144,787,000 as increases in deposits and funds from loan repayments outpaced uses of funds for loan originations, purchases of securities and repayments of borrowings.
INTEREST EXPENSE AND INTEREST-BEARING LIABILITIES
For the three-month periods, interest expense decreased $520,000 to $1,747,000 in 2021 from $2,267,000 in 2020. Interest expense on deposits decreased $567,000, as the average rate on interest-bearing deposits decreased to 0.35% in 2021 from 0.72% in 2020. The decrease in average rates on deposits includes decreases of 0.80% on time deposits, 0.13% on money market accounts, 0.07% on interest checking accounts and 0.02% on saving accounts. The change in mix of deposits also contributed to the reduction in average rate, as time deposits fell to 17.5% of total deposits in the second quarter 2021 from 25.4% in the second quarter 2020.
Average total deposits increased $570,035,000 (42.2%) to $1,919,038,000 in the second quarter from $1,349,003,000 in 2020. The increase in average balance on deposits reflects the impact of deposits assumed in the Covenant acquisition, PPP-related activity and funding from other government stimulus programs.
Interest expense on total borrowed funds increased $47,000 in 2021 as compared to 2020. The average balance of total borrowed funds decreased to $87,162,000 in the second quarter 2021 from $99,261,000 in the second quarter 2020, while the average rate on borrowed funds increased to 2.44% in the second quarter 2021 from 1.96% in the second quarter 2020. The net decrease in average balance of borrowed funds includes the impact of the prepayment of higher cost FHLB advances of $48.0 million completed in December 2020, partially offset by net increases in senior notes and subordinated debt.
Interest expense on short-term borrowings decreased $57,000 to $7,000 in 2021 from $64,000 in 2020. The average balance of short-term borrowings decreased to $6,528,000 in 2021 from $19,844,000 in 2020. The average rate on short-term borrowings decreased to 0.43% in 2021 from 1.30% in 2020, reflecting the impact of lower short term rates.
Interest expense on long-term borrowings (FHLB advances) decreased $204,000 to $109,000 in 2021 from $313,000 in 2020. The average balance of long-term borrowings was $46,788,000 in 2021, down from an average balance of $72,917,000 in 2020. Borrowings are classified as long-term within the Tables based on their term at origination or assumption in business combinations. The average rate on long-term borrowings was 0.93% in 2021 compared to 1.73% in 2020.
In May 2021, the Corporation issued unsecured senior notes with a total carrying value at issuance of $14,663,000, net of issuance costs. Interest expense on the senior notes totaled $57,000 in 2021. The average balance of the senior notes was $6,930,000 in the second quarter of 2021 at an average rate of 3.30%.
Interest expense on subordinated debt increased $251,000 to $357,000 in 2021 from $106,000 in 2020. The average balance of subordinated debt increased to $26,916,000 in 2021 from $6,500,000 in 2020 as a result of subordinated debt agreements assumed in the Covenant transaction of $10,091,000 in July 2020 and the new issue of subordinated debt with a total carrying value at issuance of $24,437,000, net of issuance costs, in May 2021, partially offset by the redemption of subordinated notes totaling $8,000,000 in June 2021. The subordinated notes issued in May 2021 bear interest at 3.25% with an effective interest rate of 3.74%, maturing in June 2031 and redeemable at par beginning in June 2026. If not redeemed, the subordinated notes will bear interest at a variable rate, resetting quarterly, from June 1, 2026 until maturity. The average rate incurred on subordinated debt was 5.32% in 2021, down from 6.56% in 2020.
More information regarding the terms of borrowed funds is provided in Note 9 to the unaudited consolidated financial statements.
Six-Month Periods Ended June 30, 2021 and 2020
For the six-month periods, fully taxable equivalent net interest income was $39,305,000 in 2021, $10,316,000 (35.6%) higher than in 2020. Interest income was $42,723,000 or $8,712,000 (25.6%) higher in 2021 as compared to 2020, while interest expense was $3,418,000 or lower by $1,604,000 (31.9%) in comparing the same periods. As presented in Table III, the Net Interest Margin was