Nature of Operations	6 Months Ended
Jun. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	1. Nature of Operations Description of Business Unless the context requires otherwise in these notes to the consolidated financial statements, the terms “SHI,” “ the “Company,” “we,” “us,” and “our” refer to Soluna Holdings, Inc. together with its consolidated subsidiaries, “SDI” refers to Soluna Digital, Inc., “SCI” refers to Soluna Computing, Inc., formerly known as EcoChain, Inc., “Soluna Cloud” or “Cloud” refers to Soluna Cloud, Inc., and “SEI” refers to Soluna Energy, Inc. Soluna Holdings, Inc. (“SHI”) is a digital infrastructure company that specializes in transforming surplus renewable energy into computing resources. The Company’s strategy is to operate modular data centers co-located with wind, solar, and hydroelectric power plants, supporting compute-intensive applications, including Bitcoin mining, generative AI, and soon-high performance computing (“HPC”). This approach aims to create a more sustainable grid while providing cost-effective and environmentally friendly computing solutions. SHI was originally incorporated in the State of New York in 1961 as Mechanical Technology, Incorporated and reincorporated in the State of Nevada on March 24, 2021. On March 23, 2021, SHI’s common stock commenced trading on the Nasdaq Stock Market LLC (“Nasdaq”). Headquartered in Albany, New York, the Company changed its name from “Mechanical Technology, Incorporated” to Soluna Holdings, Inc. on November 2, 2021. On October 29, 2021, Soluna Callisto Holdings, Inc. (“Soluna Callisto”) merged into Soluna Computing, Inc. (“SCI”), a private green data center development company and a subsidiary of SHI. MTI Instruments, Inc., a subsidiary of SHI, was sold on April 11, 2022. The Company formed a wholly owned subsidiary of SHI on December 27, 2023, Soluna Digital, Inc. (“Soluna Digital,” or “SDI”). Effective December 31, 2023, SCI transferred substantially all of its assets to SHI or its subsidiaries, including SDI. The Company sold SCI in April 2024. During fiscal year 2021, the Company commenced mining operations at its Murray, Kentucky location (“Project Sophie”) and Calvert City, Kentucky site (“Project Marie”). Project Marie was decommissioned in February 2023, while Project Sophie transitioned its focus from proprietary Bitcoin mining to hosting customers’ Bitcoin mining operations in the second quarter of 2023. All 25 MW of Project Sophie now perform data hosting services. The Company has since sold all Bitcoin miners at Project Sophie and redeployed the capital. The Company’s Texas site (“Project Dorothy”), located at a wind farm, holds the potential for up to 100 MW of power generation. By June 2024, SHI had energized 50 MW of the site across two phases, Project Dorothy 1A and 1B. As of June 30, 2025, SHI holds a 15% Class B membership interest in Soluna DVSL ComputeCo, LLC (“DVSL”), owner of Project Dorothy 1A, and a subsidiary of SHI holds a 100% Class A membership interest in DVSL. SHI also holds a 51% ownership interest in Soluna DV ComputeCo, LLC (“DVCC”), owner of Project Dorothy 1B. On July 22, 2024, the Company closed financing for the 48 MW modular data center (the “Project Dorothy 2”). Project Dorothy 2 is financed by Soluna2 SLC Fund II Project Holdco LLC, an investment vehicle of Spring Lane Capital (“SLC”) and SDI. As of June 30, 2025, SDI has 100% Class A membership and 0% Class B membership interest in Project Dorothy 2. *Going Concern and Liquidity* The Company’s condensed consolidated financial statements as of June 30, 2025 have been prepared using generally accepted accounting principles in the United States of America (“U.S. GAAP”) applicable to a going concern, which contemplates the realization of assets and liquidation of liabilities in the normal course of business. As shown in the accompanying condensed consolidated financial statements, the Company was in a net loss position, has negative working capital, and has significant outstanding debt as of June 30, 2025. In addition, Soluna MC Borrowings, LLC 2021-1 (“Borrower”), a subsidiary of Soluna MC, LLC (“Soluna MC”), a subsidiary of Soluna Digital, Inc. (“Soluna Digital” or “SDI”), a subsidiary of the Company, has a litigation matter with NYDIG ABL LLC (“NYDIG”) in relation to their Master Equipment Finance Agreement. See further discussion around the NYDIG litigation in Note 10. The Company had outstanding commitments as of June 30, 2025 related to SDI of $10.1 million in capital expenditures related to Project Dorothy 2 and Project Kati. In addition, in June 2024, Soluna AL Cloudco, LLC (“CloudCo”), a subsidiary of Soluna Cloud, entered into an agreement (the “HPE Agreement”) with Hewlett Packard Enterprise Company (“HPE”), with an initial pre-payment of $10.3 million and a total commitment of $34 million over a 36-month period. On March 24, 2025, CloudCo notified HPE of its termination of the HPE Agreement and, on March 26, 2025, HPE notified CloudCo of its termination of the HPE Agreement for cause, effective immediately, due to CloudCo’s material breach of its payment obligations that remained uncured for more than thirty (30) days. In accordance with the terms of the HPE Agreement, upon a termination for cause by HPE, CloudCo must pay HPE the remaining payment stream under the term of the HPE Agreement of approximately $19.3 million as of June 30, 2025, including all upfront payments and monthly charges, plus any fees incurred for the terminated Services (as defined in the HPE Agreement). CloudCo has not made any additional payments under the HPE Agreement since CloudCo notified HPE of its termination of the HPE Agreement. These factors, among others indicate that there is substantial doubt about the Company’s ability to continue as a going concern within one year after issuance of these condensed consolidated financial statements as of June 30, 2025, or August 14, 2025. The ability to continue as a going concern is dependent upon the Company generating profitable operations in the future and/or obtaining the necessary financing to meet its obligations and repay its liabilities arising from normal business operations when they come due. In the near term, management is evaluating and implementing different strategies to obtain financing to fund the Company’s expenses and growth to achieve a level of revenue adequate to support the Company’s current cost structure. Financing strategies may include, but are not limited to, stock issuances, project level equity, debt borrowings, partnerships and/or collaborations. If the Company is unable to meet its financial obligations, it could be forced to restructure or refinance, seek additional equity capital or sell its assets. The Company might then be unable to obtain such financing or capital or sell its assets on satisfactory terms. There can be no assurance that additional financing will be available to the Company when needed or, if available, that it can be obtained on commercially reasonable terms. If the Company is not able to obtain the additional financing on a timely basis, if and when it is needed, it will be forced to delay or scale down some or all of its development activities or perhaps even cease the operation of its business. In addition to the Company’s cash on hand for available use of approximately $9.9 million as of June 30, 2025, the Company will need to raise additional capital through financing raising activities, to meet its capital expenditure needs for its current pipeline and other operational needs. On August 12, 2024, the Company entered into a Standby Equity Purchase Agreement (the “SEPA”) with YA II PN, LTD., a Cayman Islands exempt limited company (“YA”). In accordance with the terms of the SEPA, YA has agreed to purchase up to $25 million in aggregate gross purchase price of newly issued fully paid shares of the Company’s common stock from time to time subject to the limits and the conditions of the SEPA. The Company drew on the SEPA in the first quarter of 2025, and the proceeds were used to pay debt, invest in data center projects, and for working capital and general corporate purposes. As of June 30, 2025, the Company has drawn approximately $2.0 million on the SEPA. Additionally, on April 29, 2025, the Company entered into an At the Market Offering Agreement (the “ATM Agreement”) with H.C. Wainwright & Co., LLC (“Wainwright”), as sales agent, pursuant to which the Company may offer and sell, from time to time, through Wainwright, up to $3.75 million of shares of common stock. As of June 30, 2025, the Company has drawn approximately $2.2 million pursuant to the ATM Agreement. On July 15, 2025, the Company entered into a securities purchase agreement with the purchasers signatory thereto, pursuant to which the Company received gross proceeds of $5.0 million from a public offering of common stock. See Subsequent Events: Note 16 for further details on the public offering. The Company, in 2025, will continue to look to evaluate different strategies to obtain financing to fund operations. However, management cannot provide any assurances that the Company will be successful in accomplishing additional financing or any of its other plans. These financial statements do not include any adjustments related to the recoverability and classification of assets or the amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern.

Nature of Operations

6 Months Ended

Jun. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

1. Nature of Operations

Description of Business

Unless the context requires otherwise in these notes to the consolidated financial statements, the terms “SHI,” “ the “Company,” “we,” “us,” and “our” refer to Soluna Holdings, Inc. together with its consolidated subsidiaries, “SDI” refers to Soluna Digital, Inc., “SCI” refers to Soluna Computing, Inc., formerly known as EcoChain, Inc., “Soluna Cloud” or “Cloud” refers to Soluna Cloud, Inc., and “SEI” refers to Soluna Energy, Inc.

Soluna Holdings, Inc. (“SHI”) is a digital infrastructure company that specializes in transforming surplus renewable energy into computing resources. The Company’s strategy is to operate modular data centers co-located with wind, solar, and hydroelectric power plants, supporting compute-intensive applications, including Bitcoin mining, generative AI, and soon-high performance computing (“HPC”). This approach aims to create a more sustainable grid while providing cost-effective and environmentally friendly computing solutions.

SHI was originally incorporated in the State of New York in 1961 as Mechanical Technology, Incorporated and reincorporated in the State of Nevada on March 24, 2021. On March 23, 2021, SHI’s common stock commenced trading on the Nasdaq Stock Market LLC (“Nasdaq”). Headquartered in Albany, New York, the Company changed its name from “Mechanical Technology, Incorporated” to Soluna Holdings, Inc. on November 2, 2021. On October 29, 2021, Soluna Callisto Holdings, Inc. (“Soluna Callisto”) merged into Soluna Computing, Inc. (“SCI”), a private green data center development company and a subsidiary of SHI. MTI Instruments, Inc., a subsidiary of SHI, was sold on April 11, 2022. The Company formed a wholly owned subsidiary of SHI on December 27, 2023, Soluna Digital, Inc. (“Soluna Digital,” or “SDI”). Effective December 31, 2023, SCI transferred substantially all of its assets to SHI or its subsidiaries, including SDI. The Company sold SCI in April 2024.

During fiscal year 2021, the Company commenced mining operations at its Murray, Kentucky location (“Project Sophie”) and Calvert City, Kentucky site (“Project Marie”). Project Marie was decommissioned in February 2023, while Project Sophie transitioned its focus from proprietary Bitcoin mining to hosting customers’ Bitcoin mining operations in the second quarter of 2023. All 25 MW of Project Sophie now perform data hosting services. The Company has since sold all Bitcoin miners at Project Sophie and redeployed the capital.

The Company’s Texas site (“Project Dorothy”), located at a wind farm, holds the potential for up to 100 MW of power generation. By June 2024, SHI had energized 50 MW of the site across two phases, Project Dorothy 1A and 1B. As of June 30, 2025, SHI holds a 15% Class B membership interest in Soluna DVSL ComputeCo, LLC (“DVSL”), owner of Project Dorothy 1A, and a subsidiary of SHI holds a 100% Class A membership interest in DVSL. SHI also holds a 51% ownership interest in Soluna DV ComputeCo, LLC (“DVCC”), owner of Project Dorothy 1B. On July 22, 2024, the Company closed financing for the 48 MW modular data center (the “Project Dorothy 2”). Project Dorothy 2 is financed by Soluna2 SLC Fund II Project Holdco LLC, an investment vehicle of Spring Lane Capital (“SLC”) and SDI. As of June 30, 2025, SDI has 100% Class A membership and 0% Class B membership interest in Project Dorothy 2.

Going Concern and Liquidity

The Company’s condensed consolidated financial statements as of June 30, 2025 have been prepared using generally accepted accounting principles in the United States of America (“U.S. GAAP”) applicable to a going concern, which contemplates the realization of assets and liquidation of liabilities in the normal course of business. As shown in the accompanying condensed consolidated financial statements, the Company was in a net loss position, has negative working capital, and has significant outstanding debt as of June 30, 2025. In addition, Soluna MC Borrowings, LLC 2021-1 (“Borrower”), a subsidiary of Soluna MC, LLC (“Soluna MC”), a subsidiary of Soluna Digital, Inc. (“Soluna Digital” or “SDI”), a subsidiary of the Company, has a litigation matter with NYDIG ABL LLC (“NYDIG”) in relation to their Master Equipment Finance Agreement. See further discussion around the NYDIG litigation in Note 10. The Company had outstanding commitments as of June 30, 2025 related to SDI of $10.1 million in capital expenditures related to Project Dorothy 2 and Project Kati. In addition, in June 2024, Soluna AL Cloudco, LLC (“CloudCo”), a subsidiary of Soluna Cloud, entered into an agreement (the “HPE Agreement”) with Hewlett Packard Enterprise Company (“HPE”), with an initial pre-payment of $10.3 million and a total commitment of $34 million over a 36-month period. On March 24, 2025, CloudCo notified HPE of its termination of the HPE Agreement and, on March 26, 2025, HPE notified CloudCo of its termination of the HPE Agreement for cause, effective immediately, due to CloudCo’s material breach of its payment obligations that remained uncured for more than thirty (30) days. In accordance with the terms of the HPE Agreement, upon a termination for cause by HPE, CloudCo must pay HPE the remaining payment stream under the term of the HPE Agreement of approximately $19.3 million as of June 30, 2025, including all upfront payments and monthly charges, plus any fees incurred for the terminated Services (as defined in the HPE Agreement). CloudCo has not made any additional payments under the HPE Agreement since CloudCo notified HPE of its termination of the HPE Agreement.

These factors, among others indicate that there is substantial doubt about the Company’s ability to continue as a going concern within one year after issuance of these condensed consolidated financial statements as of June 30, 2025, or August 14, 2025.

The ability to continue as a going concern is dependent upon the Company generating profitable operations in the future and/or obtaining the necessary financing to meet its obligations and repay its liabilities arising from normal business operations when they come due. In the near term, management is evaluating and implementing different strategies to obtain financing to fund the Company’s expenses and growth to achieve a level of revenue adequate to support the Company’s current cost structure. Financing strategies may include, but are not limited to, stock issuances, project level equity, debt borrowings, partnerships and/or collaborations. If the Company is unable to meet its financial obligations, it could be forced to restructure or refinance, seek additional equity capital or sell its assets. The Company might then be unable to obtain such financing or capital or sell its assets on satisfactory terms. There can be no assurance that additional financing will be available to the Company when needed or, if available, that it can be obtained on commercially reasonable terms. If the Company is not able to obtain the additional financing on a timely basis, if and when it is needed, it will be forced to delay or scale down some or all of its development activities or perhaps even cease the operation of its business.

In addition to the Company’s cash on hand for available use of approximately $9.9 million as of June 30, 2025, the Company will need to raise additional capital through financing raising activities, to meet its capital expenditure needs for its current pipeline and other operational needs. On August 12, 2024, the Company entered into a Standby Equity Purchase Agreement (the “SEPA”) with YA II PN, LTD., a Cayman Islands exempt limited company (“YA”). In accordance with the terms of the SEPA, YA has agreed to purchase up to $25 million in aggregate gross purchase price of newly issued fully paid shares of the Company’s common stock from time to time subject to the limits and the conditions of the SEPA. The Company drew on the SEPA in the first quarter of 2025, and the proceeds were used to pay debt, invest in data center projects, and for working capital and general corporate purposes. As of June 30, 2025, the Company has drawn approximately $2.0 million on the SEPA. Additionally, on April 29, 2025, the Company entered into an At the Market Offering Agreement (the “ATM Agreement”) with H.C. Wainwright & Co., LLC (“Wainwright”), as sales agent, pursuant to which the Company may offer and sell, from time to time, through Wainwright, up to $3.75 million of shares of common stock. As of June 30, 2025, the Company has drawn approximately $2.2 million pursuant to the ATM Agreement. On July 15, 2025, the Company entered into a securities purchase agreement with the purchasers signatory thereto, pursuant to which the Company received gross proceeds of $5.0 million from a public offering of common stock. See Subsequent Events: Note 16 for further details on the public offering.

The Company, in 2025, will continue to look to evaluate different strategies to obtain financing to fund operations. However, management cannot provide any assurances that the Company will be successful in accomplishing additional financing or any of its other plans. These financial statements do not include any adjustments related to the recoverability and classification of assets or the amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern.