LIQUIDITY AND CAPITAL RESOURCES
Liquidity measures the ability of the Company to meet maturing obligations and its existing commitments, to withstand fluctuations in deposit levels, to fund its operations, and to provide for customers' credit needs. The Company monitors liquidity risk through contingency planning stress testing on a regular basis. The Company seeks to avoid over-concentration of funding sources and to establish and maintain contingent funding facilities that can be drawn upon if normal funding sources become unavailable. One source of liquidity is cash and short-term assets, such as interest-bearing deposits in other banks and federal funds sold, which averaged $321.7 million during the third quarter of 2020 and $327.9 million during the first nine months of 2020. The Company's on balance sheet liquidity position can fluctuate based on short-term activity in deposits and loans.
The Company has been able to access available funding sources to address liquidity needs during the COVID-19 pandemic. In addition, the Company has been able to pledge the PPP loans to the Federal Reserve as part of its operational line of credit.
The subsidiary banks have a variety of sources of short-term liquidity available to them, including federal funds purchased from correspondent banks, FHLB advances, wholesale structured repurchase agreements, brokered deposits, lines of credit, borrowing at the Federal Reserve Discount Window, sales of securities AFS, and loan/lease participations or sales. The Company also generates liquidity from the regular principal payments and prepayments made on its loan/lease portfolio, and on the regular monthly payments on its securities portfolio.
At September 30, 2020, the subsidiary banks had 28 lines of credit totaling $749.9 million, of which $293.9 million was secured and $456.0 million was unsecured. At September 30, 2020, the Company had $749.9 million of the $749.9 million available.
At December 31, 2019, the subsidiary banks had 27 lines of credit totaling $380.6 million, of which $45.3 million was secured and $335.3 million was unsecured. At December 31, 2019, the full $380.6 million was available.
The Company has emphasized growing the number and amount of lines of credit in an effort to strengthen this contingent source of liquidity. Additionally, the Company maintains a $25.0 million secured revolving credit note with a variable interest rate and a maturity of June 30, 2021. At September 30, 2020, the full $25.0 million was available.
As of September 30, 2020, the Company had $849.6 million in average correspondent banking deposits spread over 192 relationships. While the Company believes that these funds are relatively stable, there is the potential for large fluctuations that can impact liquidity. Seasonality and the liquidity needs of these correspondent banks can impact balances. Management closely monitors these fluctuations and runs stress scenarios to measure the impact on liquidity and interest rate risk with various levels of correspondent deposit run-off.
Investing activities used cash of $837.8 million during the first nine months of 2020, compared to $235.1 million for the same period of 2019. The net decrease in federal funds sold was $9.3 million for the first nine months of 2020, compared to a net decrease of $17.1 million for the same period of 2019. The net increase in interest-bearing deposits at financial institutions was $154.2 million for the first nine months of 2020, compared to a net increase of $57.2 million for the same period of 2019. Proceeds from calls, maturities, and paydowns of securities were $72.3 million for the first nine months of 2020, compared to $45.7 million for the same period of 2019. Purchases of securities used cash of $255.5 million for the first nine months of 2020, compared to $28.1 million for the same period of 2019. Proceeds from sales of securities were $28.6 million for the first nine months of 2020, compared to $33.1 million in proceed from sales of securities for the first nine months of 2019. The net increase in loans/leases used cash of $555.3 million for the first nine months of 2020 compared to $237.3 million for the same period of 2019.
Financing activities provided cash of $701.2 million for the first nine months of 2020, compared to $206.1 million for same period of 2019. Net increases in deposits totaled $731.4 million for the first nine months of 2020, compared to $277.0 million for the same period of 2019. During the first nine months of 2020, the Company's short-term borrowings increased