Soluna Holdings Inc.

04/01/2026 | Press release | Distributed by Public on 04/01/2026 14:31

Supplemental Prospectus (Form 424B5)

Filed Pursuant to Rule 424(b)(5)

Registration No. 333-294152

PROSPECTUS

Up to $500,000,000

Common Stock

On April 29, 2025, we entered into a certain At the Market Offering Agreement, or Sales Agreement, with H.C. Wainwright & Co., LLC, or Wainwright, relating to shares of our common stock, par value $0.001 per share ("common stock"), offered by this prospectus. In accordance with the terms of the Sales Agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $500,000,000 from time to time through Wainwright.

Our common stock is listed on the Nasdaq Capital Market under the symbol "SLNH". The last reported sale price of our common stock on March 6, 2026 on the Nasdaq Capital Market was $0.77.

Sales of our common stock, if any, under this prospectus may be made in sales deemed to be "at the market offerings" as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, or the Securities Act, including sales made directly on or through the Nasdaq Capital Market, the existing trading market for our common stock, or any other existing trading market in the United States for our common stock, sales made to or through a market maker other than on an exchange or otherwise, directly to Wainwright as principal, in negotiated transactions at market prices prevailing at the time of sale or at prices related to such prevailing market prices if authorized by us in writing, and/or in any other method permitted by law. Wainwright is not required to sell any specific number or dollar amount of securities, but will act as a sales agent using commercially reasonable efforts consistent with its normal trading and sales practices, on mutually agreed terms between Wainwright and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The compensation to Wainwright for sales of common stock sold pursuant to the Sales Agreement will be equal to 3.0% of the gross proceeds of any shares of common stock sold under the Sales Agreement. In connection with the sale of the common stock on our behalf, Wainwright will be deemed to be an "underwriter" within the meaning of the Securities Act and the compensation of Wainwright will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to Wainwright with respect to certain liabilities, including liabilities under the Securities Act or the Exchange Act of 1934, as amended, or the Exchange Act. See the section titled "Plan of Distribution" on page S-12 of this prospectus. This offering pursuant to this prospectus will terminate upon the earlier of (a) the sale of shares of our common stock pursuant to this prospectus having an aggregate sales price of $500,000,000, or (b) the termination by us or Wainwright of the Sales Agreement pursuant to its terms.

Investing in our common stock involves risks. See "Risk Factors" beginning on page S-8 of this prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

H.C. Wainwright & Co.

The date of this prospectus is March 30, 2026

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TABLE OF CONTENTS

ABOUT THIS PROSPECTUS S-1
CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS S-2
PROSPECTUS SUMMARY S-3
THE OFFERING S-7
RISK FACTORS S-8
USE OF PROCEEDS S-10
DIVIDEND POLICY S-11
PLAN OF DISTRIBUTION S-12
LEGAL MATTERS S-13
EXPERTS S-14
WHERE YOU CAN FIND MORE INFORMATION S-15
INCORPORATION OF DOCUMENTS BY REFERENCE S-16
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ABOUT THIS PROSPECTUS

This prospectus is part of a shelf registration statement that we filed with the U.S. Securities and Exchange Commission, or the SEC, utilizing a "shelf" registration process. This prospectus relates to the offer and sale by us pursuant to the Sales Agreement of common stock having an aggregate offering price of $500,000,000 from time to time at prices and on terms to be determined by market conditions at the time of the offering. The $500,000,000 of shares of our common stock that may be sold under this prospectus are included in the $1,000,000,000 of shares of common stock that may be sold under the registration statement.

We provide information to you about this offering of shares of our common stock in two separate documents that are bound together: (1) this prospectus, which describes the specific details regarding this offering; and (2) the accompanying base prospectus, which provides general information, some of which may not apply to this offering. Generally, when we refer to this "prospectus," we are referring to both documents combined.. To the extent there is a conflict between the information contained in this prospectus and the information contained in any document incorporated by reference that was filed with the SEC before the date of this prospectus, you should rely on the information in this prospectus; provided that if any statement in one of these documents is inconsistent with a statement in another document having a later date, for example, a document incorporated by reference in this prospectus, the statement in the document having the later date modifies or supersedes the earlier statement.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference herein were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

You should rely only on the information contained in this prospectus, or incorporated by reference herein. We have not authorized, and Wainwright has not authorized, anyone to provide you with information that is different. The information contained in this prospectus, or incorporated by reference herein or therein is accurate only as of the respective dates thereof, regardless of the time of delivery of this prospectus or of any sale of our common stock. It is important for you to read and consider all information contained in this prospectus, including the documents incorporated by reference herein and therein, in making your investment decision. You should also read and consider the information in the documents to which we have referred you in the sections entitled "Where You Can Find More Information" and "Incorporation of Certain Information by Reference" in this prospectus.

We are offering to sell, and seeking offers to buy, the securities offered by this prospectus only in jurisdictions where offers and sales are permitted. The distribution of this prospectus and the offering of the securities offered by this prospectus in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, the offering of our common stock and the distribution of this prospectus outside the United States. This prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

When used herein, unless the context requires otherwise, references to the "Company," "we," "our" and "us" refer to Soluna Holdings, Inc., a Nevada corporation.

All trademarks or trade names referred to in this prospectus are the property of their respective owners. Solely for convenience, the trademarks and trade names in this prospectus are referred to without the ® and ™ symbols, but such references should not be construed as any indicator that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do not intend the use or display of other companies' trademarks and trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference in this prospectus contain, and our officers and representatives may from time to time make, forward-looking statements that involve substantial risks and uncertainties. In some cases, you can identify forward-looking statements by terms such as "may," "will," "should," "expect," "plan," "anticipate," "could," "intend," "target," "project," "estimate," "believe," "estimate," "predict," "potential" or "continue" or the negative of these terms or other similar expressions intended to identify statements about the future. These statements speak only as of the date of this prospectus and involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition and results of operations. These forward-looking statements include, without limitation, statements about the following:

the availability of financing opportunities, risks associated with economic conditions, dependence on management and conflicts of interest;
the ability to service debt obligations and maintain flexibility in respect of debt covenants;
economic dependence on regulated terms of service and electricity rates;
the speculative and competitive nature of the technology sector;
our ability to attract and retain hosted customers for our hosting operations;
dependency in continued growth in blockchain and cryptocurrency usage;
lawsuits and other legal proceedings and challenges;
conflict of interests with directors and management;
government regulations;
our ability to construct and complete the anticipated expansion of our data centers;
the impact of global economic and market conditions and political developments on our business, including, among others, tariffs, rising inflation and capital market disruptions, economic sanctions, bank failures, regional conflicts around the world, and economic slowdowns or recessions that may result from such developments which could harm our research and development efforts as well as the value of our common stock and our ability to access capital markets; and
other factors beyond our control.

The foregoing does not represent an exhaustive list of matters that may be covered by the forward-looking statements contained herein and in the documents incorporated by reference herein or risk factors that we are faced with that may cause our actual results to differ from those anticipate in our forward-looking statements. Factors that may affect our results include, but are not limited to, the risks and uncertainties discussed in the "Risk Factors" section on page S-8 of this prospectus, in our most recent Annual Report on Form 10-K or in other reports we file with the SEC.

Moreover, new risks regularly emerge, and it is not possible for our management to predict or articulate all risks we face, nor can we assess the impact of all risks on our business or the extent to which any risk, or combination of risks, may cause actual results to differ from those contained in any forward-looking statements. The Private Securities Litigation Reform Act of 1995 and Section 27A of the Securities Act do not protect any forward-looking statements that we make in connection with this offering. All forward-looking statements included in this prospectus and in the documents incorporated by reference in this prospectus are based on information available to us on the date of this prospectus or the date of the applicable document incorporated by reference. Except to the extent required by applicable laws or rules, we undertake no obligation to publicly update or revise any forward-looking statement, whether written or oral, that may be made from time to time, whether as a result of new information, future events or otherwise. All subsequent written and oral forward-looking statements attributable to us or persons acting on our behalf are expressly qualified in their entirety by the cautionary statements contained above and throughout this prospectus and in the documents incorporated by reference in this prospectus. We qualify all of our forward-looking statements by these cautionary statements.

You should rely only on the information in this prospectus. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely upon it.

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PROSPECTUS SUMMARY

The following summary highlights some information from this prospectus. It is not complete and does not contain all of the information that you should consider before making an investment decision. You should read this entire prospectus, including the "Risk Factors" section on page S-8 and the disclosures to which that section refers you, the financial statements and related notes and the other more detailed information appearing elsewhere or incorporated by reference into this prospectus before investing in any of the securities described in this prospectus.

Corporate Overview

Our mission is to make renewable energy a global superpower using computing as a catalyst.

We develop and operate digital infrastructure that taps into a growing global opportunity: the convergence of renewable energy and High-Performance Computing ("HPC"). We call this model Renewable Computing™.

Across the world, vast amounts of clean energy go to waste due to curtailment. At the same time, there is a critical shortage of power for energy-intensive infrastructure like Artificial Intelligence ("AI"), HPC, and Bitcoin mining. Renewable Computing™ bridges this gap-unlocking stranded renewable energy and turning it into scalable computing power.

We build, own or co-own, and operate data centers co-located with wind, solar, and hydroelectric plants. Our modular and scalable design supports high-throughput, batchable applications such as Bitcoin, and soon, HPC/AI workloads. These facilities are managed by MaestroOS™, our proprietary operating system ("MaestroOS"), which continuously analyzes signals like local power pricing, weather, grid demand, and market conditions to optimize performance and economics.

This intelligent orchestration enables long-term asset monetization and attractive returns on invested capital. Our approach is purpose-built for the energy transition. We specialize in curtailment solutions, working closely with leading renewable energy developers to access underutilized, low-cost power. Our behind-the-meter model allows us to draw energy directly from the plant or the grid, while also providing demand response services-reducing costs and enhancing grid resilience.

A key strategic advantage is our model of co-locating data centers directly with renewable power generation assets. By building behind the meter, we are able to bypass long interconnection queues and source electricity directly from the generation site. This structure not only improves power economics but also accelerates time-to-market-an increasingly important factor for companies with large, time-sensitive computing workloads such as AI and HPC.

With a repeatable strategy and a growing pipeline of projects, we are scaling a new category of digital infrastructure-one that energizes the grid, lowers computing costs, and advances a more sustainable future.

We operate across multiple business lines and generate revenue from four primary sources, as described below:

Bitcoin Mining Business - We mine Bitcoin through proprietary operations and joint ventures located at our data centers.
Bitcoin Hosting Business - We provide hosting services to third-party Bitcoin mining customers at our data centers.
High Performance Computing Business - We offer colocation and hosting services for companies seeking to train large language models ("LLMs"), fine-tune existing artificial intelligence models, and deploy other compute-intensive AI or HPC workloads.
Demand Response Business - We leverage our data center infrastructure to provide demand response services to grid operators.
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Lines of Business

Bitcoin Mining Business

We engage in proprietary Bitcoin mining, a process that verifies transactions and secures the Bitcoin blockchain. This process involves the use of specialized computing equipment to solve complex cryptographic algorithms. Miners compete to solve these algorithms; the first to do so is awarded a predetermined number of newly issued Bitcoins (the "Block Reward") and any transaction fees associated with that block.

We participate in one or more mining pools-collaborative networks of miners who combine computing power to improve the probability of earning rewards. Block Rewards earned by the pool are distributed among participants based on each member's proportional contribution. This model helps reduce revenue volatility compared to solo mining operations.

Our mining operations are energy-intensive and require significant computational resources. We operate data centers equipped with both proprietary and third-party hardware and software. Our proprietary data center operating system, MaestroOS, is used to optimize performance, manage power consumption, and increase operational efficiency.

Revenue from Bitcoin mining consists of Block Rewards and transaction fees and is recognized upon receipt in accordance with applicable accounting guidance. Upon receipt, all digital assets are promptly converted into U.S. dollars through the Coinbase cryptocurrency exchange.

The profitability of this business is affected by several variables, including the market price of Bitcoin, global network hash rate, mining difficulty, electricity and infrastructure costs, and mining pool fees. In addition, Bitcoin undergoes a periodic "halving" event approximately every four years, reducing the Block Reward and potentially impacting future revenue. For the three and nine months ended September 30, 2025, our Bitcoin Mining Business represented approximately 33% and 42% of total revenue. For the three and nine months ended September 30, 2024, our Bitcoin Mining Business represented approximately 37% and 46% of total revenue.

Bitcoin Hosting Business

We provide colocation and hosting services for third-party Bitcoin mining customers at our data centers. Customers contract space based on their power requirements. Our current customer base includes several large-scale ("Hyperscale") Bitcoin miners. Contracts typically range from 12 to 24 months in duration.

We offer two primary commercial structures:

3 Fixed-Fee Model - Customers pay a fixed fee based on the volume of energy consumed.
4 Profit-Share Model - Customers pay a share of the profits from their mining activity, with power costs passed through.

For the three and nine months ended September 30, 2025, our Bitcoin Hosting Business accounted for approximately 62% and 53% of total revenue. For the three and nine months ended September 30, 2024, our Bitcoin Hosting Business accounted for approximately 57% and 49% of total revenue. Revenue in the Bitcoin Hosting Business was concentrated among a small number of customers. For the three months ended September 30, 2025, two customers made up approximately 63% of hosting revenue and 40% of total revenue. For the nine months ended September 30, 2025, three customers made up approximately 80% of hosting revenue and 42% of total revenue.

High Performance Computing ("HPC") Business

In June 2024, we began providing GPU-as-a-Service in partnership with Hewlett Packard Enterprise Company ("HPE"), offering GPU resources to startups, enterprises, and GPU marketplaces for a fee. As further described in our Annual Report on Form 10-K for the year ended December 31, 2024, we terminated our agreement with HPE.

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We are currently developing new infrastructure projects intended to support AI and HPC workloads. These efforts include engagement with potential joint venture partners, conducting site and feasibility studies, securing access to power and land, and performing other early-stage development activities.

Our first planned AI/HPC colocation project is Project Kati, which is in advanced development. Additional projects, including the announced Project Rosa, are also in progress. For the fiscal year 2024 and the nine months ended September 30, 2025, we generated minimal revenue from our HPC Business.

Demand Response Business

We provide demand response services to grid operators and utilities by leveraging our data centers as dispatchable energy resources. In select states where we operate, our data centers are enrolled in ancillary services programs that support grid reliability.

Under these programs, we commit to reducing a facility's power consumption to a predetermined level when called upon by the grid operator. In return, we receive compensation for maintaining this dispatch capability, provided we meet specific performance criteria. For example, to qualify for compensation in a given period-typically monthly-the data center must meet minimum uptime and availability requirements.

For the three and nine months ended September 30, 2025, our Demand Response Business represented approximately 5% and 5% of total revenue. For the three and nine months ended September 30, 2024, our Demand Response Business represented approximately 6% and 5% of total revenue.

Recent Developments

Registered Direct Offering

On December 4, 2025, we entered into a securities purchase agreement with certain investors, pursuant to which we sold to the investors in a registered direct offering: (i) 5,929,944 shares of common stock, (ii) pre-funded warrants to purchase up to 12,149,200 shares of common stock, and (iii) Series C Warrants (the "Series C Warrants") to purchase up to 18,079,144 shares of common stock (the "December 2024 Offering"). The purchase price for each share of common stock and accompanying Series C Warrant sold in the December 2024 Offering was $1.77. H.C. Wainwright & Co., LLC acted as placement agent in connection with the December 2025 Offering. We received gross proceeds of approximately $32 million from the December 2025 Offering, before deducting placement agent fees and other estimated offering expenses payable by us. The December 2025 Offering closed on December 5, 2025.

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Implications of Being a Smaller Reporting Company

We qualify as a "smaller reporting company" under applicable SEC regulations. A smaller reporting company may take advantage of reduced reporting requirements that are otherwise applicable to public companies. These provisions include, but are not limited to:

being permitted to present only two years of audited financial statements and only two years of related "Management's Discussion and Analysis of Financial Condition and Results of Operations" disclosure in our periodic reports and registration statements, including this prospectus, and reduced disclosure about our executive compensation arrangements;
not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act, as amended, on the effectiveness of our internal controls over financial reporting; and
reduced disclosure obligations regarding executive compensation arrangements in our periodic reports, proxy statements and registration statements, including this prospectus.

We will continue to be a smaller reporting company as long as we have a public float (determined as of the end of our second fiscal quarter) of less than $250 million or have annual revenues of less than $100 million as of the last fiscal year for which we have audited financial statements and a public float of less than $700 million.

We have elected to take advantage of certain of the reduced disclosure obligations in the registration statement of which this prospectus is a part and may elect to take advantage of other reduced reporting requirements in future filings. As a result, the information that we provide to our stockholders may be different than you might receive from other public reporting companies in which you hold equity interests.

Corporate Information

Soluna Holdings, Inc. ("SHI"), formerly known as Mechanical Technology, Incorporated, which was originally incorporated in the State of New York in 1961, reincorporated in the State of Nevada on March 29, 2021, and is headquartered in Albany, New York. Effective November 2, 2021, the Company changed its name from "Mechanical Technology, Incorporated" (or "MTI") to "Soluna Holdings, Inc." On October 29, 2021, Soluna Callisto Holdings, Inc. 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. On March 23, 2021, our common stock commenced trading on the Nasdaq. We formed a wholly owned subsidiary of SHI on December 27, 2023, Soluna Digital, Inc. ("SDI"). Effective December 31, 2023, SCI transferred substantially all of its assets to SHI or its subsidiaries, including SDI.

Our principal executive office is located at 325 Washington Avenue Extension, Albany, NY 12205, and our phone number is (516) 216-9257. Our principal website address is www.solunacomputing.com.

Information contained in, or accessible through, our website does not constitute part of this prospectus or registration statement and inclusions of our website address in this prospectus or registration statement are inactive textual references only. You should not rely on any such information in making your decision whether to purchase our securities.

We make available free of charge on or through our website access to press releases and investor presentations, as well as all materials that we file electronically with the SEC, including our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports, filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act of 1934, as amended (the "Exchange Act"), as soon as reasonably practicable after electronically filing such materials with, or furnishing them to, the SEC. The SEC maintains an Internet website, www.sec.gov, that contains reports, proxy and information statements and other information that we file electronically with the SEC.

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THE OFFERING

Issuer Soluna Holdings, Inc.
Securities Offered by Us Pursuant to This Prospectus Common stock having an aggregate offering price of up to $500,000,000.
Common Stock Outstanding After This Offering Up to 760,178,588 shares, assuming the sale of 649,350,649 shares in this offering at a price of $0.77 per share, which was the closing price on the Nasdaq Capital Market on March 6, 2026. The actual number of shares issued will vary depending on the sales price under this offering. In addition, as there is no minimum offering amount required as a condition of this offering, the actual number of shares that may be sold is not determinable at this time.
Use of Proceeds We intend to use the net proceeds, if any, from this offering, for working capital, project-level equity, and general corporate purposes. See "Use of Proceeds" on page S-10 of this prospectus.
Risk Factors Investing in our common stock involves significant risks. See "Risk Factors" beginning on page S-8 of this prospectus and other information included or incorporated by reference into this prospectus for a discussion of factors you should carefully consider before investing in our securities.
National Securities Exchange Listing Our common stock is currently listed on the Nasdaq Capital Market under the symbol "SLNH."

The number of our common stock to be outstanding after the offering is based on 110,827,939 of our common stock outstanding as of March 6, 2026 and excludes:

2,645 shares of our common stock issuable upon the exercise of options outstanding at a weighted average exercise price of $21.46 per share;
558,980 shares of our common stock underlying restricted stock units;
6,510,416 shares of our common stock issuable upon conversion of our Series B Convertible Preferred Stock, par value $0.001 per share (the "Series B Preferred Stock"); and
22,449,840 shares of our common stock issuable upon the exercise of outstanding warrants, including pre-funded warrants, at a weighted average exercise price of $1.92 per share.
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RISK FACTORS

Investing in our securities involves a high degree of risk. Before deciding whether to invest in our securities, you should carefully consider the risk factors we describe in this prospectus and in any related free writing prospectus that we may authorize to be provided to you or in any report incorporated by reference into this prospectus, including our Annual Report on Form 10-K for the year ended December 31, 2024, or any Quarterly Report on Form 10-Q that is incorporated by reference into this prospectus. Although we discuss key risks in those risk factor descriptions, additional risks not currently known to us or that we currently deem immaterial also may impair our business. Our subsequent filings with the SEC may contain amended and updated discussions of significant risks. We cannot predict future risks or estimate the extent to which they may affect our financial performance.

Risks Relating to this Offering

We may allocate the net proceeds from this offering in ways that you or other stockholders may not approve.

We currently intend to use the net proceeds of this offering, if any, for working capital, project-level equity, and general corporate purposes, which may include capital expenditures and business expansions. This expected use of the net proceeds from this offering represents our intentions based upon our current plans and business conditions. The amounts and timing of our actual expenditures may vary significantly depending on numerous factors, including the progress of our development efforts, and any unforeseen cash needs. Because the number and variability of factors that will determine our use of the proceeds from this offering, their ultimate use may vary substantially from their currently intended use. As a result, our management will retain broad discretion over the allocation of the net proceeds from this offering and could spend the proceeds in ways that do not necessarily improve our operating results or enhance the value of our common stock. See "Use of Proceeds."

It is not possible to predict the aggregate proceeds resulting from sales made under the Sales Agreement.

Subject to certain limitations in the Sales Agreement and compliance with applicable law, we have the discretion to deliver a placement notice to Wainwright at any time throughout the term of the Sales Agreement. The number of shares that are sold through Wainwright after delivering a placement notice will fluctuate based on a number of factors, including the market price of our common stock during the sales period, the limits we set with Wainwright in any applicable placement notice, and the demand for shares of our common stock during the sales period. Because the price per share of each share sold will fluctuate during the sales period, it is not currently possible to predict the aggregate proceeds to be raised in connection with those sales.

You may experience immediate and substantial dilution in the book value per share of the common stock you purchase.

The shares sold in this offering, if any, will be sold from time to time at various prices. Because the prices per share at which shares of our common stock are sold in this offering could be substantially higher than the book value per share of our common stock, you may suffer immediate and substantial dilution in the net tangible book value of the common stock you purchase in this offering.

The shares of common stock offered hereby will be sold in "at the market offerings," and investors who buy shares at different times will likely pay different prices.

Investors who purchase shares in this offering at different times will likely pay different prices, and so may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices, and number of shares sold in this offering. In addition, subject to the final determination by our board of directors, there is no minimum or maximum sales price for shares to be sold in this offering. Investors may experience a decline in the value of the shares they purchase in this offering as a result of sales made at prices lower than the prices they paid.

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The actual number of shares we will issue under the Sales Agreement at any one time or in total, is uncertain.

Subject to certain limitations in the Sales Agreement and compliance with applicable law, we have the discretion to deliver placement notices to Wainwright at any time throughout the term of the Sales Agreement. The number of shares that are sold by Wainwright as our sales agent after we deliver a placement notice will fluctuate based on the market price of the common stock and the trading volume of our common stock during the sales period and limits we set with Wainwright.

Our articles of incorporation authorizes us to issue up to 375,000,000 shares of common stock. As of March 6, 2026, we had 110,827,939 shares of common stock outstanding and 264,172,061 available for future issuance. Until we have additional shares of common stock authorized and available, at $0.77, the last reported sale price of our common stock on March 6, 2026, we would be limited in the number of shares that we may sell pursuant to the Sales Agreement and this prospectus supplement.

You may experience future dilution as a result of future equity offerings.

In order to raise additional capital, we may in the future offer additional shares of common stock or other securities convertible into or exchangeable for our common stock at prices that may not be the same as the price per share in this offering. We may sell shares or other securities in another offering at a price per share that is less than the price per share paid by the investors in this offering, and investors purchasing shares or other securities in the future could have rights superior to existing stockholders. The price per share at which we sell additional shares of common stock, or securities convertible or exchangeable into shares of common stock, in future transactions may be higher or lower than the price per share paid by investors in this offering. If any of the above should occur, our stockholders, including investors who purchase shares of common stock in this offering, will experience additional dilution, and any such issuances may result in downward pressure on the price of our common stock.

We do not currently intend to pay dividends or other distributions on our common stock in the foreseeable future, and consequently, any gains from an investment in our common stock will likely depend on appreciation in the price of our common stock.

We have never declared or paid cash dividends on our common stock and do not anticipate paying any cash dividends or other distributions to holders of our common stock in the foreseeable future. Consequently, investors must rely on sales of their common stock after price appreciation, which may never occur, as the only way to realize any future gains on their investments. There is no guarantee that our common stock will appreciate in value or even maintain the price at which the stockholders have purchased their shares.

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USE OF PROCEEDS

We currently intend to use the net proceeds from this offering, if any, for working capital, project-level equity, and general corporate purposes.

The timing and amount of our actual expenditures will be based on many factors, including cash flows from operations and the anticipated growth of our business. As of the date of this prospectus, we cannot specify with certainty all of the particular uses for the net proceeds to us from this offering. As a result, our management will have broad discretion regarding the timing and application of the net proceeds from this offering. Pending their ultimate use, we intend to invest the net proceeds in short-term, investment-grade, interest-bearing instruments.

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DIVIDEND POLICY

We have never declared or paid cash dividends on our capital stock. We currently intend to retain our future earnings, if any, for use in our business and therefore do not anticipate paying cash dividends or other distributions in the foreseeable future. Payment of future dividends or other distributions, if any, will be at the discretion of our board of directors, subject to applicable law, after taking into account various factors, including our financial condition, operating results, current and anticipated cash needs and plans for expansion.

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PLAN OF DISTRIBUTION

We entered into the Sales Agreement with Wainwright, pursuant to which we may issue and sell from time to time shares of our common stock having an aggregate offering price of up to the amount set forth on the cover page of this prospectus, as supplemented from time to time, through or to Wainwright acting as sales agent or principal. Sales of the common stock, if any, will be made by any method permitted by law deemed to be an "at-the-market offering" as defined in Rule 415(a)(4) promulgated under the Securities Act, including sales made directly on or through Nasdaq Capital Market, the existing trading market for our common stock, or any other existing trading market in the United States for our common stock, sales made to or through a market maker other than on an exchange or otherwise, directly to Wainwright as principal, in negotiated transactions at market prices prevailing at the time of sale or at prices related to such prevailing market prices if authorized by us in writing, and/or in any other method permitted by law.

Wainwright will offer our common stock at prevailing market prices subject to the terms and conditions of the Sales Agreement. We will designate the number of shares we desire to sell, the time period during which sales are requested to be made, any limitation on the number of shares that may be sold in one day and any minimum price below which sales may not be made. Subject to the terms and conditions of the Sales Agreement, Wainwright will use its commercially reasonable efforts consistent with its normal trading and sales practices and applicable law and regulations to sell on our behalf all of the shares of common stock requested to be sold by us. We or Wainwright may suspend the offering of the common stock being made through Wainwright under the Sales Agreement upon proper notice to the other party and pursuant to the terms of the Sales Agreement.

Settlement for sales of common stock will occur on the first trading day following the date on which any sales are made (or such shorter settlement cycle as may be in effect under the Exchange Act from time to time), or on some other date that is agreed upon by us and Wainwright in connection with a particular transaction, in return for payment of the net proceeds to us. Sales of our common stock as contemplated in this prospectus will be settled through the facilities of The Depository Trust Company or by such other means as we and Wainwright may agree upon. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

We will pay Wainwright a cash commission equal to 3.0% of the gross sales price per share of common stock sold by Wainwright under the Sales Agreement. Because there is no minimum offering amount required as a condition to this offering, the actual total offering amount, sales commissions and net proceeds to us, if any, are not determinable at this time. Pursuant to the terms of the Sales Agreement, we have agreed to pay Wainwright a fee not to exceed $50,000 for the reasonable fees and expenses of its legal counsel (excluding any periodic due diligence fees) incurred in connection with entering into the transactions contemplated by the Sales Agreement, which was paid at commencement of the offering. Additionally, pursuant to the terms of the Sales Agreement, we have also agreed to reimburse Wainwright $3,500 per due diligence update session conducted in connection with each such date we file our Annual Report on Form 10-K or Quarterly Reports on Form 10-Q or an additional prospectus supplement for this offering. We estimate that the total expenses of the offering payable by us, excluding commissions payable to Wainwright under the Sales Agreement, will be approximately $200,000, assuming we sell the entire amount offered pursuant to this prospectus. We will disclose in our Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q, as applicable, the number of shares of our common stock sold through Wainwright under the Sales Agreement, the net proceeds to us and the compensation paid by us with respect to sales under the Sales Agreement during the relevant quarter.

In connection with the sales of common stock on our behalf, Wainwright will be deemed to be an "underwriter" within the meaning of the Securities Act, and the compensation paid to Wainwright will be deemed to be underwriting commissions or discounts. We have agreed in the Sales Agreement to provide indemnification and contribution to Wainwright against certain liabilities, including liabilities under the Securities Act.

The offering of our shares of common stock pursuant to the Sales Agreement will terminate upon termination of the Sales Agreement or as otherwise permitted therein. We or Wainwright may terminate the Sales Agreement at any time, pursuant to the terms of the Sales Agreement.

To the extent required by Regulation M, Wainwright will not engage in any market making activities involving our shares of common stock while the offering is ongoing under this prospectus.

From time to time, Wainwright and its affiliates have and may provide in the future various advisory, investment and commercial banking and other services to us and our affiliates in the ordinary course of business, for which they have received and may continue to receive customary fees and commissions. Wainwright acted as placement agent in connection with our registered direct offering in December 2025 and received customary compensation. In addition, in the ordinary course of its various business activities, Wainwright and its affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (which may include bank loans) for their own account and for the accounts of their customers. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. Wainwright or its affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

This summary of the material provisions of the Sales Agreement does not purport to be a complete statement of its terms and conditions. The Sales Agreement is filed as an exhibit to the registration statement of which this prospectus forms a part.

This prospectus in electronic format may be made available on a website maintained by Wainwright and Wainwright may distribute this prospectus electronically.

Our transfer agent and registrar for our common stock is Equiniti Trust Company, LLC.

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LEGAL MATTERS

The validity of the shares of common stock offered by this prospectus will be passed upon by Brownstein Hyatt Farber Schreck, LLP, Las Vegas, Nevada. Certain legal matters in connection with the common stock offered hereby will be passed upon for us by Lowenstein Sandler LLP. Wainwright is being represented in connection with this offering by Ellenoff Grossman & Schole LLP, New York, New York.

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EXPERTS

The consolidated balance sheets of Soluna Holdings, Inc. and its subsidiaries as of December 31, 2024 and 2023, and the related consolidated statements of operations, changes in equity, and cash flows for each of the years then ended have been audited by UHY LLP, independent registered public accounting firm, as stated in their report which is incorporated herein by reference. Such financial statements have been incorporated herein by reference in reliance on the report of such firm given upon their authority as experts in accounting and auditing.

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WHERE YOU CAN FIND MORE INFORMATION

This prospectus constitutes a part of a registration statement on Form S-3 filed under the Securities Act. As permitted by the SEC's rules, this prospectus and any prospectus supplement, which form a part of the registration statement, do not contain all the information that is included in the registration statement. You will find additional information about us in the registration statement. Any statements made in this prospectus or any prospectus supplement concerning legal documents are not necessarily complete and you should read the documents that are filed as exhibits to the registration statement or otherwise filed with the SEC for a more complete understanding of the document or matter.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read, without charge, and copy the documents we file at the SEC's public reference rooms in Washington, D.C. at 100 F Street, NE, Room 1580, Washington, DC 20549. You can request copies of these documents by writing to the SEC and paying a fee for the copying cost. Please call the SEC at 1-800-SEC-0330 for further information on the public reference rooms. Our SEC filings are also available to the public at no cost from the SEC's website at http://www.sec.gov.

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INCORPORATION OF DOCUMENTS BY REFERENCE

We have filed a registration statement on Form S-3 with the SEC under the Securities Act. This prospectus is part of the registration statement but the registration statement includes and incorporates by reference additional information and exhibits. The SEC permits us to "incorporate by reference" the information contained in documents we file with the SEC, which means that we can disclose important information to you by referring you to those documents rather than by including them in this prospectus. Information that is incorporated by reference is considered to be part of this prospectus, and you should read it with the same care that you read this prospectus. Information that we file later with the SEC will automatically update and supersede the information that is either contained, or incorporated by reference, in this prospectus, and will be considered to be a part of this prospectus from the date those documents are filed.

We have filed with the SEC, and incorporate by reference in this prospectus:

our Annual Report on Form 10-K for the fiscal year ended December 31, 2024 filed with the SEC on March 31, 2025;
our Quarterly Reports on Form 10-Q for the period ended March 31, 2025, filed with the SEC on May 15, 2025, for the period ended June 30, 2025, filed with the SEC on August 14, 2025, and for the period ended September 30, 2025, filed with the SEC on November 14, 2025;
our Current Reports on Form 8-K filed with the SEC on February 10, 2025, March 18, 2025, March 27, 2025, March 28, 2025, April 29, 2025, May 8, 2025, July 3, 2025, July 9, 2025, July 17, 2025, August 8, 2025, August 20, 2025, September 16, 2025, September 23, 2025, October 6, 2025, October 21, 2025, November 10, 2025, December 5, 2025 and January 20, 2026 (other than any portions thereof deemed furnished and not filed); and
the description of our common stock contained in our Registration Statement on Form 8-A, filed with the SEC on March 22, 2021, as updated by the Description of Securities set forth on Exhibit 4.14 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, as filed with the SEC on March 31, 2025, including any amendments thereto or reports filed for the purposes of updating this description.

We also incorporate by reference all additional documents that we file with the SEC under the terms of Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act that are made after the initial filing date of the registration statement of which this prospectus is a part until the offering of the particular securities covered by a prospectus supplement or term sheet has been completed. We are not, however, incorporating, in each case, any documents or information that we are deemed to furnish and not file in accordance with SEC rules.

You may request, and we will provide you with, a copy of these filings, at no cost, by contacting us at:

Soluna Holdings, Inc.

325 Washington Avenue Extension

Albany, NY 12205

(518) 218-2550

Attn: Christopher Gandolfo

[email protected]

S-16

Up to $500,000,000

Common Stock

PROSPECTUS

H.C. Wainwright & Co.

March 30,2026

Soluna Holdings Inc. published this content on April 01, 2026, and is solely responsible for the information contained herein. Distributed via EDGAR on April 01, 2026 at 20:31 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]