balance sheet liquidity to pre-COVID-19 levels since the first quarter of 2020 while continuing to build our contingent funding availability during the second and third quarters of 2020.
Our total commitments to extend credit and available credit lines are discussed in the following section of this Management’s Discussion and Analysis of Financial Condition and Results of Operations, including a table presenting our comparative exposure at September 30, 2020 and December 31, 2019.
CDs due within one year totaled $369.0 million, or 18.7% of total deposits, and $458.9 million, or $26.8% of total deposits, at September 30, 2020 and December 31, 2019, respectively. If we do not retain these deposits, we may be required to seek other sources of funds, including securities sales and FHLB advances. Depending on market conditions, we may be required to pay higher rates on our deposits or other borrowings than we currently pay on the CDs held in our portfolio. We believe, however, based on historical experience and current market interest rates that we will retain upon maturity a large portion of our CDs with maturities of one year or less as of September 30, 2020.
Our primary investing activity is originating loans. During the first nine months of 2020, cash used to fund net loan growth was $138.5 million, up $55.4 million from $83.1 million of cash used to fund net loan growth for the first nine months of 2019. PPP loans originated during 2020, net of unamortized deferred fees and origination costs, accounted for $196.4 million of the net loan growth. During the first nine months of 2020 we purchased $303.5 million of securities while securities sales, maturities, calls, and principal repayments totaled $145.5 million; this resulted in net securities purchases of $158.0 million. For the same period in 2019, we purchased $24.5 million of securities while securities sales, maturities, calls, and principal repayments totaled $87.3 million; this resulted in net securities sales, maturities, calls and principal repayments of $62.8 million.
Financing activities consist primarily of activity in deposit accounts and FHLB advances. For the first nine months of 2020, our deposit growth was $258.4 million compared to December 31, 2019. Deposit flows are affected by the overall level of interest rates, the interest rates and products offered by us and our local competitors, our utilization of institutional deposits sources, and by other factors.
Liquidity management is both a daily and long-term function of business management. If we require funds beyond our ability to generate them internally, borrowing agreements exist with the FHLB, which provide an additional source of funds. FHLB advances decreased to $200.0 million at September 30, 2020 compared to $285.0 million at December 31, 2019. At September 30, 2020, we had an available line of credit for $615.8 million at the FHLB, with borrowings limited to a total of $472.9 million based on pledged collateral. This provides us with $272.9 million of borrowing availability at September 30, 2020. We also utilized the PPPLF during the second quarter of 2020, with total borrowings outstanding of $31.1 million at September 30, 2020. We have additional PPPLF borrowing capacity, based on the principal balance of unpledged PPP loans, totaling $168.9 million at September 30, 2020. Subsequent to September 30, 2020, we repaid all PPPLF borrowings and have no plans to further utilize the PPPLF.
The Bank is subject to various regulatory capital requirements, including a risk-based capital measure. The risk-based capital guidelines include both a definition of capital and a framework for calculating risk-weighted assets by assigning balance sheet assets and off-balance sheet items to broad risk categories. At September 30, 2020 and December 31, 2019, we exceeded all regulatory capital requirements. We are considered “well capitalized” under regulatory guidelines.
Commitments, Contingent Liabilities, and Off-Balance Sheet Arrangements
We are party to financial instruments with off-balance sheet risk in the normal course of business to meet the financial needs of our customers. These financial instruments are limited to commitments to originate loans and involve, to varying degrees, elements of credit, interest rate, and liquidity risk. These do not represent unusual risks, and management does not anticipate any losses that would have a material effect on us.