Liquidity and Capital Resources
Our principal capital requirements are to fund sales and marketing, invest in research and development and capital equipment, and to fund working capital needs. We calculate working capital as current assets less current liabilities.
Our principal sources of liquidity are our cash, cash equivalents, cash flows from operations and financing activities. Our ability to manage cash and cash equivalents may be limited, as our primary cash flows are dictated by the terms of our sales and supply agreements, contractual obligations, debt instruments and legal and regulatory requirements. From time to time, we may sell accounts receivable to third parties under factoring agreements or engage in accounts receivable discounting to facilitate the collection of cash. In addition, from time to time, we may make payments to our vendors on extended terms with their consent. As of June 30, 2023, we did not have any accounts payable on extended terms or payment deferment with our vendors.
As of June 29, 2018, our Korean subsidiary entered into an arrangement whereby it (i) acquired a water treatment facility from SK hynix for $4.2 million to support our fabrication facility in Gumi, Korea, and (ii) subsequently sold the water treatment facility for $4.2 million to a third party management company that we engaged to run the facility for a 10-year term beginning July 1, 2018. As of June 30, 2023, the outstanding obligation of this arrangement is approximately $22.4 million for remaining service term through 2028.
As of June 30, 2023, cash and cash equivalents held by our Korean subsidiary were $166.3 million, which represents 96% of our total cash and cash equivalents on a consolidated basis. We currently believe that we will have sufficient cash reserves from cash on hand and expected cash from operations to fund our operations as well as capital expenditures for the next 12 months and the foreseeable future.
Working Capital
Our working capital balance as of June 30, 2023 was $228.9 million compared to $290.6 million as of December 31, 2022. The $61.7 million decrease was primarily attributable to a $52.5 million decrease in cash and cash equivalents resulted primarily from our continued execution of expanded stock repurchase program, and the 2023 Resignation Program that we offered and paid to certain employees during the first half of 2023.
Cash Flows from Operating Activities
Cash outflow used in operating activities totaled $1.9 million for the six months ended June 30, 2023, compared to $25.0 million of cash inflow provided by operating activities for the six months ended June 30, 2022. The net operating cash outflow for the six months ended June 30, 2023 reflects our net loss of $25.4 million, as adjusted favorably by $26.5 million, which mainly consisted of depreciation and amortization, provision for severance benefits, and net foreign currency loss, and net unfavorable impact of $3.0 million from changes of operating assets and liabilities.
Cash Flows from Investing Activities
Cash outflow used in investing activities totaled $6.4 million for the six months ended June 30, 2023, compared to $6.7 million of cash outflow used in investing activities for the six months ended June 30, 2022. The $0.3 million decrease was primarily attributable to a $4.8 million net decrease in hedge collateral, which was offset in part by a $4.4 million net increase in guarantee deposits.
Cash Flows from Financing Activities
Cash outflow used in financing activities totaled $37.1 million for the six months ended June 30, 2023, compared to $0.3 million of cash outflow used in financing activities for the six months ended June 30, 2022. The financing cash outflow for the six months ended June 30, 2023 was primarily attributable to a payment of $36.4 million for the repurchases of our common stock pursuant to our expanded stock repurchase program and a payment of $0.4 million for the repurchase of our common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock units. The financing cash outflow for the six months ended June 30, 2022 was primarily attributable to a payment of $1.8 million for the repurchase of our common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock units, which was offset entirely by $1.8 million of proceeds received from the issuance of common stock in connection with the exercise of stock options.
Capital Expenditures
We routinely make capital expenditures for fabrication facility maintenance, enhancement of our existing facility and reinforcement of our global research and development capability. For the six months ended June 30, 2023, capital expenditures for property, plant and equipment were $1.5 million, which remained flat, compared to $1.5 million for the six months ended June 30, 2022. The capital expenditures for the six months ended June 30, 2023 and 2022 were related to meeting our customer demand and supporting technology and facility improvement at our fabrication facility.
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