Alto Ingredients, Inc.

This Proxy Statement is being furnished in connection with the solicitation of proxies by our Board of Directors (“Board”) for use at the 2024 annual meeting (“Annual Meeting”) of stockholders to be held on Thursday, June 20, 2024, at 9:00 a.m., local time, at our headquarters at 1300 South Second Street, Pekin, Illinois 61554, and at any adjournment(s) or postponement(s) of the Annual Meeting. We are providing this Proxy Statement and the accompanying proxy card to our stockholders on or about May 3, 2024. Our stockholders are invited to attend the Annual Meeting and are requested to vote on the proposals described in this Proxy Statement.

IMPORTANT NOTICE REGARDING THE INTERNET AVAILABILITY

OF PROXY MATERIALS FOR THE 2024 ANNUAL MEETING

OF STOCKHOLDERS TO BE HELD JUNE 20, 2024

This Proxy Statement and our Annual Report on Form 10-K for the year ended December 31, 2023 are available at the website address at http://proxyvote.com. You will need your control number located in our Notice of Internet Availability of Proxy Materials sent to you to access the proxy materials. Your control number is also located in your proxy card and your voting instruction form. You are encouraged to access and review all of the important information contained in the proxy materials before voting. The Annual Report is not to be regarded as proxy soliciting material or as a communication through which any solicitation of proxies is made.

What items will be voted on at the Annual Meeting?

Stockholders will vote on four items at the Annual Meeting:

What are the Board’s Voting Recommendations?

The Board recommends that you vote your shares as follows:

Who is entitled to vote?

To be able to vote, you must have been a stockholder on April 22, 2024, the record date for determination of stockholders entitled to notice of and to vote at the Annual Meeting. As of the record date, 76,628,808 shares of our voting common stock, par value $0.001 per share (“common stock”), and 926,942 shares of our Series B Cumulative Convertible Preferred Stock, par value $0.001 per share (“Series B Preferred Stock”), were issued and outstanding.

As of the record date, 896 shares of our non-voting common stock, par value $0.001 per share (“Non-Voting Common Stock”), were also issued and outstanding. Holders of our Non-Voting Common Stock are entitled to notice of and to attend the Annual Meeting but are not entitled to vote on any matters in respect of their shares of Non-Voting Common Stock.

How many votes do I have?

Holders of common stock and Series B Preferred Stock will vote at the Annual Meeting as a single class on all matters. Each holder of common stock is entitled to one vote per share held, and each holder of Series B Preferred Stock is entitled to approximately 0.03 votes per share held. As a result, a total of 76,655,289 votes may be cast at the Annual Meeting, of which holders of common stock will be entitled to cast 76,628,808 votes and holders of Series B Preferred Stock will be entitled to cast 26,481 votes.

What is a quorum?

For business to be conducted at the Annual Meeting, a quorum must be present. The presence at the Annual Meeting, either in person or by proxy, of holders of shares of outstanding common stock and Series B Preferred Stock entitled to vote and representing at least a majority of our outstanding voting power will constitute a quorum for the transaction of business. Accordingly, shares representing 38,327,645 votes must be present in person or by proxy at the Annual Meeting to constitute a quorum.

Abstentions and broker non-votes will be counted for the purpose of determining whether a quorum is present for the transaction of business.

If a quorum is not present, the Annual Meeting will be adjourned until a quorum is obtained.

What are abstentions and broker non-votes?

An “abstention” is the voluntary act of not voting by a stockholder who is present at a meeting in person or by proxy and entitled to vote. “Broker non-votes” refers to shares held by a brokerage firm or other nominee (for the benefit of its client) that are represented at the meeting, but with respect to which such broker or nominee is not instructed to vote on a particular proposal and does not have discretionary authority to vote on that proposal.

If you are a beneficial owner whose shares are held in street name and you do not submit voting instructions to your broker, your broker may generally vote your shares in its discretion on routine matters. We believe that Proposal Four is routine and may be voted on by your broker if you do not submit voting instructions. However, pursuant to the rules of The Nasdaq Stock Market (“Nasdaq”), brokers do not have the discretion to vote their clients’ shares on non-routine matters unless the broker receives voting instructions from the beneficial owner. Proposals One, Two and Three are considered non-routine matters. Consequently, if your shares are held in street name, you must provide your broker with instructions on how to vote your shares in order for your shares to be voted on Proposals One, Two and Three.

What are the general effects of abstentions and broker non-votes?

Brokers who hold shares for the accounts of their clients may vote such shares either as directed by their clients or in their own discretion as permitted under Nasdaq’s listing rules. For purposes of the Annual Meeting, brokers or nominees are permitted to vote their clients’ proxies in their own discretion as to the ratification of the appointment of our independent registered public accounting firm if the clients have not furnished voting instructions within 10 days of the meeting. Certain proposals other than the ratification of the appointment of the independent registered public accounting firm are “non-discretionary” and brokers or nominees who have received no instructions from their clients do not have discretion to vote on those items. Abstentions and broker non-votes will not be counted as a vote “for” or “against” any matter, though in certain cases abstentions will have the same effect as votes against a matter as they will be counted toward the tabulation of votes present or represented on the matter. Broker non-votes will not be counted as shares entitled to vote and accordingly will not affect the outcome with respect to any matter to be voted on at the Annual Meeting.

Please note that brokers may not vote your shares on the election of directors or other non-routine matters in the absence of your specific instructions as to how to vote, thus we strongly encourage you to provide instructions to your broker regarding the voting of your shares you hold in “street name” or through a broker or other nominee.

What vote is required to approve each proposal?

Proposal One

The six nominees receiving the highest number of affirmative votes of the outstanding shares of common stock and Series B Preferred Stock, voting together as a single class, present at the Annual Meeting in person or represented by proxy and entitled to vote, will be elected as directors to serve until the next annual meeting of stockholders and/or until their successors are duly elected and qualified. Abstentions will have no effect on the outcome of the election of nominees for director. Should any nominee(s) become unavailable to serve prior to the Annual Meeting, the proxies will be voted by the proxy holders for such other person(s) as may be designated by our Board or for such lesser number of nominees as may be prescribed by the Board. Votes cast for the election of any nominee who has become unavailable will be disregarded.

Proposal Two

Under Proposal Two, our stockholders will have an advisory vote on executive compensation as described in this Proxy Statement (commonly referred to as “say-on-pay”). The votes under Proposal Two are, however, only advisory in nature, and the outcome of stockholder votes on Proposal Two will not be binding upon us, or our Compensation Committee or full Board. However, our Compensation Committee and our full Board will consider the results of the votes when making future decisions regarding our executive compensation policies and practices and in determining the frequency of future say-on-pay votes.

Proposals Three and Four

The affirmative vote of a majority of the votes of the shares of our common stock and Series B Preferred Stock, voting together as a single class, present at the Annual Meeting in person or represented by proxy and entitled to vote, is required for approval of Proposals Three and Four. Abstentions will be counted toward the tabulation of votes present or represented on these proposals and will have the same effect as votes against Proposals Three and Four.

How do I vote?

If you are a “registered holder,” that is, your shares are registered in your own name through our transfer agent, and you are viewing this Proxy Statement over the Internet you may vote electronically over the Internet. For those stockholders who receive a paper proxy in the mail, you may also vote electronically over the Internet or by telephone, or by completing and mailing the proxy card provided. The website identified in our Notice of Internet Availability of Proxy Materials provides specific instructions on how to vote electronically over the Internet. Stockholders who receive a paper proxy by mail, and who elect to vote by mail, should complete and return the mailed proxy card in the prepaid and addressed envelope that was enclosed with the proxy materials.

If your shares are held in “street name,” that is, your shares are held in the name of a brokerage firm, bank or other nominee, you will receive instructions from your record holder that must be followed for your record holder to vote your shares per your instructions. Your broker will send you a Notice of Internet Availability of Proxy Materials which contains instructions on how to access the website to vote your shares electronically over the Internet or by telephone. If, however, you have elected to receive paper copies of our proxy materials from your brokerage firm, bank or other nominee, you will receive an enclosed voting instruction form. Please complete and return the enclosed voting instruction form in the addressed, postage paid envelope provided.

Stockholders who have previously elected to access our proxy materials and annual report electronically over the Internet will continue to receive an email, referred to in this Proxy Statement as an email notice, with information on how to access the proxy information and voting instructions.

Only proxy cards and voting instruction forms that have been signed, dated and timely returned, and only shares that have been timely voted electronically or by telephone will be counted in the quorum and voted.The Internet and telephone voting facilities will close at 11:59 p.m. Eastern Time, Monday, June 17, 2024, for shares held in a plan, and at 11:59 p.m. Eastern Time, Wednesday, June 19, 2024, for shares held directly.

Stockholders who vote over the Internet or by telephone need not return a proxy card or voting instruction form by mail, but may incur costs, such as usage charges, from telephone companies or Internet service providers. You may also vote your shares in person at the Annual Meeting. If you are a registered holder, you may request a ballot at the Annual Meeting. If your shares are held in street name and you wish to vote in person at the meeting, you must obtain a proxy issued in your name from the record holder (e.g., your broker) and bring it with you to the Annual Meeting. We recommend that you vote your shares in advance as described above so that your vote will be counted if you later decide not to attend the Annual Meeting.

What if I receive more than one Notice of Internet Availability of Proxy Materials, email notice, proxy card or voting instruction form?

If you receive more than one Notice of Internet Availability of Proxy Materials, email notice, proxy card or voting instruction form because your shares are held in multiple accounts or registered in different names or addresses, please vote your shares held ineach accountto ensure that all of your shares will be voted.

I share an address with another stockholder, and we received only one paper copy of the proxy materials. How may I obtain an additional copy of the proxy materials?

We have adopted a Securities and Exchange Commission approved procedure called “householding.” Under this procedure, we deliver a single copy of the Notice of Internet Availability of Proxy Materials and, if applicable, our proxy materials to multiple stockholders who share the same address unless we have received contrary instructions from one or more of such stockholders. This procedure reduces our printing costs, mailing costs and fees. Stockholders who participate in householding will continue to be able to access and receive separate proxy cards. Upon written or oral request, we will deliver promptly a separate copy of the Notice of Internet Availability of Proxy Materials and, if applicable, our proxy materials to any stockholder at a shared address to which we delivered a single copy of any of these materials. To receive a separate copy, or, if a stockholder is receiving multiple copies, to request that we only send a single copy of the Notice of Internet Availability of Proxy Materials and, if applicable, our proxy materials, such stockholder may contact us as follows:

Alto Ingredients, Inc.

Attention: Investor Relations

1300 South Second Street

Pekin, Illinois 61554

telephone (833) 710-ALTO

Stockholders who hold shares in street name may contact their brokerage firm, bank, broker-dealer, or other similar organization to request information about householding.

Who will count the votes and how will my vote(s) be counted?

All votes will be tabulated by the inspector of elections appointed for the Annual Meeting, who will separately tabulate affirmative and negative votes, abstentions and broker non-votes.

If your proxy is properly submitted, the shares represented thereby will be voted at the Annual Meeting in accordance with your instructions. If you are a registered holder and you do not specify how the shares represented thereby are to be voted, your shares will be voted “FOR” the election of each of the six nominees to our Board listed in the proxy, “FOR” the approval of each of Proposals Two, Three and Four, and in the discretion of the proxy holder(s) as to any other matters that may properly come before the Annual Meeting or any adjournment(s) or postponement(s) of the Annual Meeting, as well as any procedural matters. If your shares are held in street name and you do not specify how the shares represented thereby are to be voted, your broker may exercise its discretionary authority to vote on Proposal Four.

Can I change my vote after I have voted?

If your shares are registered in your name, you may revoke or change your vote at any time before the Annual Meeting by voting again electronically over the Internet or telephone, if timely (see “How do I vote?” above), or by filing a notice of revocation or another proxy card with a later date with our Secretary at Alto Ingredients, Inc., 1300 South Second Street, Pekin, Illinois 61554. If you are a registered stockholder and attend the Annual Meeting and vote by ballot, any proxy that you submitted previously to vote the same shares will be revoked automatically and only your vote at the Annual Meeting will be counted. If your shares are held in street name, you should contact the record holder to obtain instructions if you wish to revoke or change your vote before the Annual Meeting. Please note that if your shares are held in street name, your vote in person at the Annual Meeting will not be effective unless you have obtained and present a proxy issued in your name from the record holder.

Who will bear the cost of soliciting proxies?

We will bear the entire cost of soliciting proxies for the Annual Meeting, including the cost of preparing, assembling, printing and mailing the Notice of Internet Availability of Proxy Materials, this Proxy Statement, the proxy card and any additional solicitation materials furnished to our stockholders. Copies of solicitation materials will be furnished to brokerage firms, fiduciaries and custodians holding shares in their names that are beneficially owned by others so that they may forward the solicitation materials to the beneficial owners. We may reimburse such persons for their reasonable expenses in forwarding solicitation materials to beneficial owners. The original solicitation of proxies may be supplemented by solicitation by personal contact, telephone, facsimile, email or any other means by our directors, officers or employees, and we will reimburse any reasonable expenses incurred for that purpose. No additional compensation will be paid to those individuals for any such services.

The matters to be considered and acted upon at the Annual Meeting are referred to in the preceding notice and are discussed below more fully.