of contingent assets and liabilities. Estimates are used in accounting for, among other things, revenue recognition, lease right-of-use assets and liabilities, contract loss accruals, excess, slow-moving and obsolete inventories, product warranty accruals, loss accruals on service agreements, share-based compensation expense, allowance for doubtful accounts, depreciation and amortization, impairment of goodwill and in-process research and development intangible assets, impairment of long-lived assets (including project assets), and contingencies. Estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the consolidated financial statements in the period they are determined to be necessary. Due to the inherent uncertainty involved in making estimates, actual results in future periods may differ from those estimates.
Liquidity
Our principal sources of cash have been proceeds from the sale of our products and projects, electricity generation revenues, research and development and service agreements with third parties, sales of our common stock through public equity offerings, and proceeds from debt, project financing and tax monetization transactions. We have utilized this cash to accelerate the commercialization of our solid oxide platforms, develop new capabilities to separate and capture carbon, develop and construct project assets, invest in capital improvements and expansion of our operations, perform research and development on Advanced Technologies, pay down existing outstanding indebtedness, and meet our other cash and liquidity needs.
As of April 30, 2023, unrestricted cash and cash equivalents totaled $246.8 million compared to $458.1 million as of October 31, 2022. During the six months ended April 30, 2023, the Company invested $138.2 million in United States (U.S.) Treasury Securities and $63.3 million of the U.S. Treasury Securities matured. The amortized cost of the U.S. Treasury Securities outstanding as of April 30, 2023 totaled $76.4 million as of April 30, 2023 compared to $0 as of October 31, 2022 and is classified as Investments - short-term on the Consolidated Balance Sheets. The maturity dates for the outstanding U.S. Treasury Securities range from May 4, 2023 to October 5, 2023.
On July 12, 2022, the Company entered into an Open Market Sale Agreement with Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canaccord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC (the “Open Market Sale Agreement”) with respect to an at the market offering program under which the Company may, from time to time, offer and sell up to 95.0 million shares of the Company’s common stock. From the date of the Open Market Sale Agreement through April 30, 2023, the Company sold approximately 19.4 million shares under the Open Market Sale Agreement at an average sale price of $3.60 per share, resulting in gross proceeds of approximately $70.0 million before deducting sales commissions and fees. During the three and six months ended April 30, 2023, approximately 0.9 million shares were sold under the Open Market Sale Agreement at an average sale price of $3.02 per share, resulting in gross proceeds of approximately $2.9 million. As of April 30, 2023, approximately 75.6 million shares were available for issuance under the Open Market Sale Agreement. The Company currently intends to use the net proceeds from this offering to accelerate the development and commercialization of its product platforms (including, but not limited to, its solid oxide and carbon capture platforms), for project development, market development, and internal research and development, to invest in capacity expansion for solid oxide and carbonate fuel cell manufacturing, and for project financing, working capital support, and general corporate purposes. The Company may also use the net proceeds from this offering to invest in joint ventures, acquisitions, and strategic growth investments and to acquire, license or invest in products, technologies or businesses that complement its business. See Note 11. “Stockholders’ Equity” for additional information regarding the Open Market Sale Agreement.
We believe that our unrestricted cash and cash equivalents, expected receipts from our contracted backlog, funds received upon the maturity of U.S. Treasury Securities, and release of short-term restricted cash less expected disbursements over the next twelve months will be sufficient to allow the Company to meet its obligations for at least one year from the date of issuance of these financial statements.
To date, we have not achieved profitable operations or sustained positive cash flow from operations. The Company’s future liquidity, for fiscal year 2023 and in the long-term, will depend on its ability to (i) timely complete current projects in process within budget, (ii) increase cash flows from its generation operating portfolio, including by meeting conditions required to timely commence operation of new projects, operating its generation operating portfolio in compliance with minimum performance guarantees and operating its generation operating portfolio in accordance with revenue expectations, (iii) obtain financing for project construction and manufacturing expansion, (iv) obtain permanent financing for its projects once constructed, (v) increase order and contract volumes, which would lead to additional product sales, service agreements and generation revenues, (vi) obtain funding for and receive payment for research and development