During the nine months ended September 30, 2020, our operating activities used approximately $11.9 million in cash and cash equivalents, which was more than our net loss of $11.3 million primarily as a result of a decrease in working capital, excluding cash and cash equivalents, totaling $1.7 million and non-cash adjustments for the warrant derivative and PPP funding totaling $0.7 million; partially off-set by non-cash charges related to depreciation and amortization, stock-based compensation totaling $1.8 million.
Net Cash Used in Investing Activities
During the nine months ended September 30, 2021, $97,000 in cash and cash equivalents was used to acquire manufacturing machinery and equipment.
During the nine months ended September 30, 2020, $48,000 in cash and cash equivalents was used to acquire manufacturing machinery and equipment.
Net Cash Provided by Financing Activities
During the nine months ended September 30, 2021, we received gross proceeds of approximately $10.5 million from the sale of approximately 6.2 million shares of common stock pursuant to the ATM equity offering program, which was partially offset by offering-related costs of $0.5 million. In addition, we also received proceeds of $0.2 million from investor warrant exercises and stock option exercises.
During the nine months ended September 30, 2020, we received gross proceeds of $15.1 million from the sale of 23.7 million shares of common stock pursuant to the ATM equity offering program, which was partially offset by offering-related costs of $0.9 million. In addition, we also received proceeds of $0.5 million from investor warrant exercises.
Liquidity and Capital Resources
Since inception, we have not generated operating revenue or profits. Over this period, we have continued to be focused on research and clinical development activities for the advancement of Ampion towards multiple BLA submissions; all of which has required raising a substantial amount of capital. As of September 30, 2021, we do not have a fixed and determinable committed source of liquidity to meet our expected obligations over the next twelve months. Specifically, we had $17.1 million of cash and cash equivalents as of September 30, 2021.
Although the ATM and/or other equity financing programs are not committed sources of liquidity, based on expected access to the ATM, consistent with previous periods, and potential for future equity financing programs, we project that we will have sufficient liquidity to fund operations through the first quarter of 2023. Our projection is based on many assumptions that may prove to be incorrect. In addition, as the global pandemic continues in an unpredictable manner, its effect on our business operations and ability to raise capital through the ATM equity offering, or otherwise, remains highly uncertain and subject to change. While we believe the studies currently being conducted will be successful, we anticipate that we will seek to raise additional capital investments in both the near and long-term to enable us to primarily support clinical development of Ampion and existing base business operations. We intend to continue our close evaluation of the overall capital markets to determine the appropriate timing and funding level for any such capital raising activities, which will primarily depend on our stock price and existing market conditions relative to our need for funds at such time.
The audit report on our financial statements for the fiscal year ended December 31, 2020 contains an explanatory paragraph indicating that there was substantial doubt about our ability continue as a going concern. In order to address the going concern, we have prepared a projection through November 30, 2022. Our projection reflects cash requirements for fixed, recurring base business expenses such as payroll, legal and accounting, patents and overhead, and incremental costs supporting our current and projected clinical development programs.
In May 2020, the shelf registration statement was declared effective by the SEC and, as of September 30, 2021, we had approximately $66.8 million available for issuance under the shelf registration statement with approximately 82.3 million authorized shares of common stock remaining available for issuance.