June 30, 2019. We have implemented measures to reduce our costs while our operations are affected by COVID-19, including furlough of certain employees, deferral of capital projects, and reduction of third-party professional services.
Depreciation and amortization. Depreciation and amortization expense increased $3.0 million to $4.9 million for the six months ended June 30, 2020 from $1.9 million for the six months ended June 30, 2019 due to the addition of the Kona Grill restaurants.
Transaction and integration costs. In the six months ended June 30, 2020, we incurred transaction and integration costs of $1.1 million related to the Kona Grill acquisition, which closed on October 4, 2019. Over the remainder of 2020, we intend to continue to integrate Kona Grill by leveraging our corporate infrastructure, our bar-business knowledge and unique Vibe Dining program, to elevate the brand experience and drive improved performance.
COVID-19 related expenses. In the six months ended June 30, 2020, we incurred approximately $2.0 million of direct costs related to COVID-19, composed primarily of payments to employees for paid-time off during restaurant closures, inventory waste, rent and rent related costs for closed and limited-operations restaurants from the day that the dining room closed, sanitation supplies and safety precautions taken to prevent the spread of COVID-19.
Lease termination expenses. In the six months ended June 30, 2020, lease termination expense was approximately $0.3 million. Lease termination expenses are costs associated with closed, abandoned and disputed locations or disputed leases.
Pre-opening expenses. Pre-opening expenses for the six months ended June 30, 2019 were $0.5 million related to the development of our owned STK restaurant in Nashville, Tennessee which opened in June 2019.
Interest expense, net of interest income. Interest expense, net of interest income was approximately $2.4 million and $0.5 million for the six months ending June 30, 2020 and 2019, respectively.
(Benefit) provision for income taxes. The benefit for income taxes for the six months ended June 30, 2020 was a tax benefit of $3.9 million compared to tax expense of $0.1 million for the six months ended June 30, 2019. Our annualized effective tax rate is estimated at 32.4% for 2020 compared to 10.2% for the six months ended June 30, 2019.
Net loss attributable to noncontrolling interest. Net loss attributable to noncontrolling interest was $0.7 million compared to net income of $0.1 million for the six months ended June 30, 2020 and 2019, respectively, due to the impact of COVID-19.
Liquidity and Capital Resources
Executive Summary
Our principal liquidity requirements are to meet our lease obligations, our working capital and capital expenditure needs and to pay principal and interest on our outstanding indebtedness. Subject to our operating performance, which, if significantly adversely affected, would adversely affect the availability of funds, we expect to finance our operations for at least the next 12 months, including the costs of opening currently planned new restaurants, through cash provided by operations, use of proceeds from the CARES Act Loans, borrowings on our Credit Agreement and construction allowances provided by landlords of certain locations. We believe the combination of the aforementioned items are adequate to support our immediate business operations and plans. As of June 30, 2020, we had cash and cash equivalents of approximately $23.5 million which includes $10.2 million in cash from the CARES Act Loans. We had $47.8 million in long-term debt, which consisted of our Credit Agreement and an equipment financing agreement, and $18.3 million in CARES Act Loans as of June 30, 2020. As of June 30, 2020, the availability on our revolving credit facility was $10.7 million, subject to the restrictions described in Note 5.
In the six months ended June 30, 2020, our capital expenditures were $1.7 million. Our future cash requirements will depend on many factors, including the pace of our expansion, conditions in the retail property development market, construction costs, the nature of the specific sites selected for new restaurants, and the nature of the specific leases and associated tenant improvement allowances available, if any, as negotiated with landlords. Additionally, under our current capital light strategy, we plan to enter into management and license agreements for the operation of STK restaurants where we are not required to contribute significant capital upfront.
Our operations have not required significant working capital, and, like many restaurant companies, we have negative working capital. Revenues are received primarily in credit card or cash receipts, and restaurant operations do not require significant receivables or inventories, other than our wine inventory. In addition, we receive trade credit for the purchase of food, beverages and supplies, thereby reducing the need for incremental working capital to support growth.