2020. The increase in purchases of pledged AFS securities was due to an increase in our collateral requirements related to our guarantee obligation for loans under the Fannie Mae DUS program as a result of increases in the DUS servicing portfolio. The increase in cash used for acquisitions was due to a year-over-year increase in the size and number of companies acquired. The increase in distributions from joint ventures was related to a reduction in the number of loans originated by the joint venture due to the COVID-19 Crisis.
The change in cash provided by financing activities was primarily attributable to the change in net warehouse borrowings period to period, partially offset by increases in cash dividends paid, repurchases of noncontrolling interests, and net repayments of interim warehouse notes payable. The change in net borrowings of warehouse notes payable during the first six months of 2020 was due to a larger increase in the unpaid principal balance of LHFS funded by Agency Warehouse Facilities (as defined below) from December 31, 2019 to June 30, 2020 than from December 31, 2018 to June 30, 2019. During 2020, the unpaid principal balance of LHFS funded by Agency Warehouse Facilities increased $946.5 million from their December 31, 2019 balance compared to an increase of $228.6 million during the same period in 2019. Additionally, as of December 31, 2019, we funded $109.0 million of the LHFI with our own cash, resulting in lower repayments of warehouse notes payable for the six months ended June 30, 2020 than during the same period in 2019.
The change in net borrowings of interim warehouse notes payable was principally due to interim loan origination and repayment activity period over period. During 2019, we originated several loans that were fully funded with corporate cash and had multiple payoffs of loans. During 2020, we had no originations and significant payoff activity, leading to a change from net borrowings to net repayments period over period. The increase in cash used for purchase of noncontrolling interest was a result of our purchase of noncontrolling interests from one of the members of WDIS in the second quarter of 2020, a unique transaction. The increase in cash dividends paid was the result of our increasing the dividends paid per share by 20% year over year.
Liquidity and Capital Resources
Uses of Liquidity, Cash and Cash Equivalents
Our significant recurring cash flow requirements consist of (i) short-term liquidity necessary to fund loans held for sale; (ii) liquidity necessary to fund loans held for investment under the Interim Program; (iii) liquidity necessary to pay cash dividends; (iv) liquidity necessary to fund our portion of the equity necessary for the operations of the Interim Program JV; (v) working capital to support our day-to-day operations, including servicing advances debt service payments and payments for salaries, commissions, and income taxes; and (vi) working capital to satisfy collateral requirements for our Fannie Mae DUS risk-sharing obligations and to meet the operational liquidity requirements of Fannie Mae, Freddie Mac, HUD, Ginnie Mae, and our warehouse facility lenders. Due to recent market developments as a result of the COVID-19 Crisis, we expect to experience an increase in our short term cash flow needs for servicing advances of principal and interest and guarantee fees related to certain Fannie Mae and HUD loans that are serviced and asset-managed by us and that are currently delinquent or in forbearance. The advances for principal and interest are guaranteed to be repaid to us by Fannie Mae and HUD.
Fannie Mae has established standards for capital adequacy and reserves the right to terminate our servicing authority for all or some of the portfolio if at any time it determines that our financial condition is not adequate to support our obligations under the DUS agreement. We are required to maintain acceptable net worth as defined in the standards, and we satisfied the June 30, 2020 requirements. The net worth requirement is derived primarily from unpaid balances on Fannie Mae loans and the level of risk-sharing. At June 30, 2020, the net worth requirement was $216.6 million and our net worth, as defined in the requirements, was $861.6 million, as measured at our wholly owned operating subsidiary, Walker & Dunlop, LLC. As of June 30, 2020, we were required to maintain at least $42.9 million of liquid assets to meet our operational liquidity requirements for Fannie Mae, Freddie Mac, HUD, Ginnie Mae and our warehouse facility lenders. As of June 30, 2020, we had operational liquidity, as defined in the requirements, of $325.0 million, as measured at our wholly owned operating subsidiary, Walker & Dunlop, LLC.
We paid a cash dividend of $0.36 per share in each of the first and second quarters of 2020, which is 20% higher than the quarterly dividends paid in 2019. On August 4, 2020, the Company’s Board of Directors declared a dividend of $0.36 per share for the third quarter of 2020. The dividend will be paid September 8, 2020 to all holders of record of the Company’s restricted and unrestricted common stock as of August 21, 2020. Over the past three years, we have returned $181.0 million to investors in the form of the repurchase of 1.9 million shares of our common stock under share repurchase programs for a cost of $89.8 million and cash dividend payments of $91.2 million. Additionally, we have invested $141.5 million in acquisitions and the purchase of mortgage servicing rights. We occasionally use cash to fully fund some loans held for investment or loans held for sale instead of using our warehouse lines. As of June 30, 2020, we used corporate cash to fully fund loans held for investment with an unpaid principal balance of $70.6 million. In response to the pullback in lending on