placement of $27 million in subordinated notes on August 26, 2021 which required additional expenses to be recognized during the third quarter of 2021. The original subordinated debt and trust preferred securities that the new debt replaced did not leave the balance sheet until September 30, 2021 as per terms required to appropriately retire the existing debt. Therefore, there was one full month of the new and the old debt instruments being on our balance sheet in September causing additional interest expense. The Company was also required to immediately write off the remaining portion of the unamortized issuance costs from both original debt instruments which generated $202,000 of additional borrowings interest expense in the third quarter of 2021. Sightly offsetting these higher costs was an increase in interest income from the securities portfolio due to a higher volume of securities. As a result of the increased level of liquidity on the Company’s balance sheet, management elected to more profitably deploy these funds into the securities portfolio as opposed to leaving them in low yielding federal funds sold. Finally, and also favorably impacting this segment was the recognition of an $84,000 security sale gain in 2021 after no gain was recognized last year.
…..BALANCE SHEET…..The Company’s total consolidated assets were $1.34 billion at September 30, 2021, which increased by $59.2 million, or 4.6%, from the December 31, 2020 asset level. This change was related, primarily, to increased levels of cash and cash equivalents, investment securities, and loans. Specifically, cash and cash equivalents increased $4.5 million, or 14.2%, as the Company experienced a significant influx of deposits resulting from the government stimulus programs and financial assistance provided to municipalities and school districts. Our liquidity position was also positively impacted by the Somerset County branch and deposit acquisition completed in May 2021, which provided approximately $42 million of additional deposits. These deposit increases were partially offset by the maturity of a $33 million institutional deposit late in the third quarter of 2021. Total investment securities increased $25.9 million, or 13.8%, as the steepening of the U.S. Treasury yield curve in the latter part of the first quarter improved the yield for federal agency mortgage-backed securities and federal agency bonds, making these types of securities more attractive for purchase. The Company also continued to purchase corporate and taxable municipal securities. In addition, loans, net of unearned fees, and loans held for sale increased by $17.7 million, or 1.8%, as a result of the Company’s participation in the PPP and higher levels of commercial real estate and residential mortgage loan production. Finally, other assets increased $13.4 million, or 131.4%, as a result of a reclassification of the accrued pension liability, which had a positive balance of $17.2 million as of September 30, 2021, from other liabilities to other assets. The balance of the accrued pension liability became a positive value as a result of the $8.0 million contribution made in 2021 and the revaluation of the obligation due to the recognition of the settlement charge.
Total deposits increased by $89.5 million, or 8.5%, in the first nine months of 2021. As previously mentioned, this robust growth is the result of the government stimulus programs and the Somerset County branch acquisition which were partially offset by the maturity of a large institutional deposit. As of September 30, 2021, the 25 largest depositors represented 19.3% of total deposits, which is a decrease from December 31, 2020 when it was 21.1%. Total borrowings have decreased by $40.2 million, or 35.2%, since year-end 2020. The decrease was driven, primarily, by a lower level of both short-term borrowings and FHLB term advances. Specifically, at September 30, 2021, the Company had no short-term borrowings outstanding as compared to $24.7 million at December 31, 2020. In addition, FHLB term advances decreased by $21.3 million, or 32.8%, and totaled $43.7 million at September 30, 2021. The current strong liquidity position has allowed the Company to paydown short-term borrowings and FHLB advances. However, the Company continues to utilize the FHLB term advances to help manage interest rate risk. Partially offsetting the decrease in short-term and FHLB borrowings was the previously mentioned subordinated debt transaction. The Company completed a private placement of $27 million in fixed-to-floating rate subordinated notes on August 26, 2021 and used approximately $20 million of the net proceeds to retire its existing subordinated debt and trust preferred securities.
The Company’s total shareholders’ equity increased by $9.3 million, or 8.9%, over the first nine months of 2021 due to the retention of earnings more than offsetting our common stock dividend payments to shareholders. Additionally, the recording of the settlement charge in connection with the defined benefit pension plan and the revaluation of the pension obligation had a positive impact on accumulated other comprehensive loss.
The Company continues to be considered well capitalized for regulatory purposes with a total capital ratio of 13.61%, and a common equity tier 1 capital ratio of 9.95% at September 30, 2021. See the discussion of the Basel III capital requirements under the Capital Resources section below. As of September 30, 2021, the Company’s book value per common share was $6.66 and its tangible book value per common share (non-GAAP) was $5.85. When compared to December 31, 2020, book value per common share improved by $0.54 per common share and tangible book value per