As filed with the Securities and Exchange Commission on August 6, 2021

Registration No. 333-255741

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

Amendment No. 3

to

FORM S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

GREENIDGE GENERATION HOLDINGS INC.

(Exact name of registrant as specified in its charter)

590 Plant Road

Dresden, NY 14441

(315) 536-2359

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Jeffrey E. Kirt

Chief Executive Officer

590 Plant Road

Dresden, NY 14441

(315) 536-2359

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this registration statement and upon completion of the merger described in the accompanying proxy statement/prospectus.

If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box.  ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for comply with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of Securities Act.  ☐

If applicable, place an X in the box to designate the appropriate rule provision relied upon in conducting this transaction:

CALCULATION OF REGISTRATION FEE

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Commission, acting pursuant to such Section 8(a), may determine.

Information contained herein is subject to completion or amendment. A registration statement relating to these securities has been filed with the Securities and Exchange Commission. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statement becomes effective. This proxy statement/prospectus shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any jurisdiction in which such offer, solicitation or sale would be unlawful.

PRELIMINARY—SUBJECT TO COMPLETION—DATED [*], 2021

PROXY STATEMENT FOR SPECIAL MEETING OF STOCKHOLDERS OF

and

PROSPECTUS FOR 2,998,261 SHARES OF CLASS A COMMON STOCK OF

MERGER PROPOSALS—YOUR VOTE IS VERY IMPORTANT

[ __ ], 2021

Dear Support Stockholder:

You are cordially invited to a special meeting of stockholders of Support.com, Inc. to be held on [ __ ] 2021 at 8:00 a.m., Pacific Time, at [ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _]. At the special meeting, you will be asked to vote on the important matters described in detail in the notice of special meeting of stockholders and the proxy statement/prospectus accompanying this letter.

The proxy statement/prospectus is being provided to you as a stockholder of Support.com, Inc., which we refer to as “Support”, in connection with the proposed merger with a subsidiary of Greenidge Generation Holdings Inc., a Delaware corporation, which we refer to as “Greenidge”. These terms and others used in this introduction are defined in the proxy statement/prospectus under the caption “Frequently Used Terms”.

At the special meeting, you will be asked to vote on the adoption of an agreement and plan of merger, dated as of March 19, 2021 (the “Signing Date”), as it may be amended from time to time (the “Merger Agreement”), by and among Support, Greenidge and GGH Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of Greenidge (“Merger Sub”), pursuant to which Merger Sub will be merged with and into Support, with Support continuing as the surviving corporation and a wholly-owned subsidiary of Greenidge (such transaction, the “Merger”) as more fully described in the proxy statement/prospectus. The Merger Agreement is attached to the proxy statement/prospectus as Annex A.

Under the Merger Agreement, the aggregate consideration payable to holders of shares of Support common stock, Support options and Support awards consists of 2,998,261 shares of class A common stock of Greenidge. It is expected that immediately following the closing of the Merger, the 2,998,261 shares of class A common stock payable as merger consideration will represent approximately 7.7% of the outstanding capital stock and approximately 0.9% of the voting power of Greenidge and the current stockholders of Greenidge will own approximately 90.0% of the outstanding capital stock of Greenidge and approximately 99.0% of the voting power of Greenidge. It is also expected Greenidge will qualify as a “controlled company” and will be exempt from certain Nasdaq corporate governance requirements as its largest existing stockholder, Atlas Capital Resources (A9) LP, together with its affiliates, is expected to own, immediately following the closing of the merger, approximately 68.8% of the outstanding capital stock and approximately 76.2% of the voting power of Greenidge.

If the Merger is completed, at the effective time of the Merger and subject to the terms and conditions set forth in the Merger Agreement, except for shares held in treasury by Support, each share of Support common stock that is issued and outstanding will be cancelled and automatically converted into the right to receive a number of shares of class A common stock equal to the Exchange Ratio.

The Exchange Ratio is a fraction, expressed as a decimal rounded to the nearest one-thousandth, equal to the quotient of (i) 2,998,261 shares of class A common stock divided by (ii) the fully diluted amount of outstanding shares of common stock of Support as calculated pursuant to the Merger Agreement.

Assuming a price per share of Support common stock of $[ _ _ ] (which is the VWAP for the ten-trading day period ending on [ _ _ ] 2021) and that the fully diluted amount of Support common stock is [ _ _ ], then the Exchange Ratio would be [ _ _ ]. Note that this is only an illustrative Exchange Ratio, and the final Exchange Ratio will be determined pursuant to the formulas in the Merger Agreement and announced immediately prior to the Closing.

Greenidge has applied to list its class A common stock on the Nasdaq Capital Market (“Nasdaq”) under the trading symbol “GREE.” The approval of such listing, including as to the shares of class A common stock issued in the Merger, subject only to official notice of issuance, is a condition to the obligations of Support and Greenidge to complete the Merger.

Shares of class A common stock, including the shares that will be issued to Support stockholders in connection with the Merger, are entitled to one vote per share. Shares of class B common stock, which are held by Greenidge’s existing shareholders or are issuable upon conversion of Greenidge’s existing series A preferred stock, have 10 votes per share. A description of the terms of Greenidge’s capital stock is described in more detail elsewhere in the proxy statement/prospectus under the caption “Description of Securities”.    

In connection with the entry into the Merger Agreement, Support also entered into a subscription agreement with 210 Capital, LLC (the “Investor”). Pursuant to the subscription agreement, the Investor acquired 3,909,871 shares of Support common stock, representing approximately 16.6% of the issued and outstanding shares of Support common stock, pro forma for such issuance. In addition, in connection with the Merger Agreement, the Investor and the directors and certain executive officers of Support, who together with the Investor held an aggregate of approximately 30% of the outstanding shares of Support common stock as of the Signing Date, entered into a voting support agreement with Greenidge to, among other things, vote the shares of Support common stock that they beneficially own in favor of the Merger and grant Greenidge an irrevocable proxy to vote their shares in such manner if they fail to perform their obligations under this voting support agreement. Each of these agreements is described in more detail elsewhere in the proxy statement/prospectus. The voting support agreement is attached to the proxy statement/prospectus as Annex B and the subscription agreement is attached as Annex C.

The board of directors of Support has unanimously determined that the Merger and the other transactions contemplated by the Merger Agreement are fair to, advisable and in the best interests of Support and its stockholders, approved and declared advisable the Merger Agreement and recommends that Support stockholders vote “FOR” the adoption of the Merger Agreement.

At the special meeting, Support stockholders will also be asked to vote on (i) a proposal to approve, on an advisory (non-binding) basis, compensation that will or may be paid or provided to named executive officers of Support in connection with the Merger (the “Compensation Proposal”) and (ii) a proposal to approve the adjournment of the special meeting, if necessary, to permit further solicitation of proxies if there are not sufficient votes to approve the proposal to adopt the Merger Agreement (the “Adjournment Proposal”).

The board of directors of Support unanimously recommends that Support stockholders vote “FOR” the Compensation Proposal and “FOR” the Adjournment Proposal.

Support’s board of directors has fixed 5 p.m. Eastern Time on [ _ _ ] 2021 as the record date for determination of Support stockholders entitled to notice of, and to vote on, all matters presented at the special meeting, or any adjournment or postponement thereof.

The accompanying proxy statement/prospectus provides important information regarding the special meeting and a detailed description of the Merger Agreement, the Merger and the other proposals described above, as well as detailed business and financial information about Greenidge. You are urged to read carefully the accompanying proxy statement/prospectus, the annexes included with the proxy statement/prospectus and the documents incorporated by reference into the proxy statement/prospectus. Please pay particular attention to and read carefully the section “Risk Factors” beginning on page 35 of the accompanying proxy statement/prospectus. You can also obtain information about Support from documents that it has previously filed with the Securities and Exchange Commission.

Your vote is very important, regardless of the number of shares you own. Whether or not you expect to attend the special meeting in person, please vote or otherwise submit a proxy to vote your shares as promptly as possible so that your shares may be represented and voted at the special meeting. If your shares are held in the name of a bank, broker or other nominee holder of record, please follow the instructions on the voting instruction form furnished to you by such record holder.

If you have any questions or need assistance voting your shares, please contact our proxy solicitor:

Harkins Kovler, LLC

3 Columbus Circle, 15FL

New York, NY 10019

Toll: +1 (212) 468-5380

Toll Free: +1 (800) 326-5997

Email: SPRT@harkinskovler.com

Sincerely,

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued under the accompanying proxy statement/prospectus or determined that the accompanying proxy statement/prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

The accompanying proxy statement/prospectus is dated [ __ ], 2021 and is first being mailed or otherwise delivered to Support stockholders on or about [ __ ], 2021.

Support.com, Inc.

1521 Concord Pike (US 202), Suite 301

Wilmington, DE 19803

(650) 556-9440

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS

TO BE HELD ON [ _ _ ] 2021

Notice is hereby given that Support.com, Inc. (“Support”) will hold a special meeting of stockholders on [ _ _ ] 2021 at 8:00 a.m., Pacific Time, at [ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _]. The special meeting will be held for the purpose of allowing stockholders to consider and vote upon the following matters:

Support’s board of directors has unanimously determined that the Merger Agreement and the transactions contemplated thereby, as well as the other proposals set forth above, are fair to, advisable and in the best interests of Support and its stockholders, and recommends that stockholders vote “FOR” each proposal.

Support’s board of directors has fixed 5 p.m. Eastern Time on [ _ _ ] 2021 as the record date for the determination of the stockholders entitled to vote at the special meeting, or any adjournment or postponement thereof. Only stockholders of record at the record date are entitled to notice of, and to vote at, the special meeting, or any adjournment or postponement thereof. For the ten days prior to the special meeting, a list of stockholders entitled to vote at the special meeting will be available for examination by any stockholder of record for purposes germane to the special meeting, by requesting a copy of such list by email at SPRT@harkinskovler.com or by phone call at +1 (800) 326-5997. Such list will also be available for examination at the special meeting. Any stockholder of record in attendance at the special meeting and entitled to vote may do so in person, even if such stockholder returned a proxy.

Support is actively monitoring the circumstances surrounding the coronavirus (COVID-19) pandemic and is sensitive to the public health and travel concerns stockholders may have and the protocols or restrictions that federal, state, and local governments may impose. In the event it is not possible or advisable to hold the special meeting in person, Support will publicly announce a determination to hold a virtual special meeting by filing a notice of the change(s) to the special meeting, and in a press release available at Support’s website as soon as practicable before the special meeting. In the event the special meeting is conducted virtually, it will be held at the same time and on the same date as indicated above, via a live audio webcast. You or your proxyholder will be able to participate, vote and examine the list of stockholders at a virtual special meeting in the event that the special meeting is not held in person.

By Order of the Board of Directors,

Lance Rosenzweig

Chief Executive Officer

Wilmington, DE

[            ], 2021

YOUR VOTE IS IMPORTANT!

WHETHER OR NOT YOU EXPECT TO ATTEND THE SPECIAL MEETING IN PERSON, YOU ARE URGED TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE (1) VIA THE INTERNET, (2) BY TELEPHONE OR (3) BY COMPLETING, SIGNING AND DATING THE ENCLOSED PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED.

The accompanying proxy statement/prospectus provides important information regarding the special meeting and a detailed description of the Merger Agreement, the Merger and the other proposals described above. You are urged to read carefully and in their entirety the accompanying proxy statement/prospectus, the annexes included with the proxy statement/prospectus and the documents incorporated by reference into the accompanying proxy statement/prospectus. If you have any questions concerning the Merger Agreement, the Merger, the special meeting or the accompanying proxy statement/prospectus, would like additional copies of the accompanying proxy statement/prospectus or need help voting your shares, please contact our proxy solicitor:

Harkins Kovler, LLC

3 Columbus Circle, 15FL

New York, NY 10019

Toll: +1 (212) 468-5380

Toll Free: +1 (800) 326-5997

Email: SPRT@harkinskovler.com

TABLE OF CONTENTS

i

ii

iii

ANNEXES

iv

REFERENCES TO ADDITIONAL INFORMATION

This proxy statement/prospectus incorporates by reference important business and financial information about Support from other documents that are not included in or delivered with this proxy statement/prospectus. For a list of the specific documents incorporated by reference into this proxy statement/prospectus, see “Where You Can Find More Information” beginning on page 182.

You can obtain any of the documents incorporated by reference into this proxy statement/prospectus without charge by requesting them in writing or by telephone as follows:

For information related to Support:

Support.com, Inc.

777 S. Figueroa Street, Suite 4600

DPT# 2009

Los Angeles, California 90017

Telephone: (650) 556-9440

or

Harkins Kovler, LLC

3 Columbus Circle, 15FL

New York, NY 10019

Toll: +1 (212) 468-5380

Toll Free: +1 (800) 326-5997

Email: SPRT@harkinskovler.com

To receive timely delivery of the documents in advance of the special meeting, you should make your request no later than [                ], 2021, which is five business days before the special meeting.

In addition, you may obtain copies of documents filed by Support with the SEC on Support’s website at www.support.com. We are not incorporating the contents of the websites of Support or any other entity into this proxy statement/prospectus.

ABOUT THIS PROXY STATEMENT/PROSPECTUS

This proxy statement/prospectus, which forms part of a registration statement on Form S-4 filed with the SEC by Greenidge, constitutes a prospectus of Greenidge under Section 5 of the Securities Act, with respect to the shares of class A common stock of Greenidge to be issued to Support stockholders pursuant to the Merger Agreement. This document also constitutes a proxy statement of Support under Section 14(a) of the Exchange Act.

You should rely only on the information contained or incorporated by reference into this proxy statement/prospectus with respect to the Merger. No one has been authorized to provide you with information that is different from that contained in, or incorporated by reference into, this proxy statement/prospectus with respect to the Merger. This proxy statement/prospectus is dated as of the date set forth on the cover hereof. You should not assume that the information contained in this proxy statement/prospectus is accurate as of any date other than that date. You should not assume that the information incorporated by reference into this proxy statement/prospectus is accurate as of any date other than the date of such incorporated document. Neither the mailing of this proxy statement/prospectus to Support stockholders nor the issuance by Greenidge of its class A common stock in connection with the Merger will create any implication to the contrary.

Information contained in this proxy statement/prospectus regarding Greenidge has been provided by Greenidge, and information contained in this proxy statement/prospectus regarding Support has been provided by Support.

This proxy statement/prospectus does not constitute an offer to sell or a solicitation of an offer to buy any securities, or the solicitation of a proxy, in any jurisdiction to or from any person to whom it is unlawful to make any such offer or solicitation in such jurisdiction.

1

INDUSTRY AND MARKET DATA

This proxy statement/prospectus contains information concerning the market and industry in which Greenidge conducts its business. Greenidge operates in an industry in which it is difficult to obtain precise industry and market information. Greenidge has obtained market and industry data in this proxy statement/prospectus from industry publications and from surveys and studies conducted by third parties that Greenidge believes to be reliable, including information produced by S&P Global, Blockchain.com, BitOoda Research and Digiconomist. Greenidge cannot assure you of the accuracy and completeness of such information, and it has not independently verified the market and industry data contained in this proxy statement/prospectus or the underlying assumptions relied on therein. Industry publications, research, studies and forecasts generally state that the information they contain has been obtained from sources believed to be reliable, but that the accuracy and completeness of such information is not guaranteed. As a result, you should be aware that any such market, industry and other similar data may not be reliable. While Greenidge is not aware of any misstatements regarding any industry data presented in this proxy statement/prospectus, such data involves risks and uncertainties and is subject to change based on various factors, including those discussed under the section entitled “Risk Factors” below.

Forecasts and other forward-looking information obtained from these sources are subject to the same qualifications and uncertainties as the other forward-looking statements in this proxy statement/prospectus. These forecasts and forward-looking information are subject to uncertainty and risk due to a variety of factors, including those described under “Risk Factors.” These and other factors could cause actual results to differ materially from those expressed in any forecasts, estimates or other forward-looking statements.

2

FREQUENTLY USED TERMS

Unless otherwise stated or unless the context otherwise requires, (i) “Greenidge” refers to, as dictated by the context, Greenidge Generation Holdings Inc. either by itself or together with its consolidated subsidiaries prior to the Merger and, following consummation of the Merger, together with Support, (ii) “Support” refers to Support.com, Inc., which, following consummation of the Merger, will be a wholly-owned subsidiary of Greenidge, and (iii) “Merger Sub” means GGH Merger Sub, Inc., a Delaware corporation.

The terms “we,” “us,” and “our” are used to refer to either “Greenidge” or “Support” as specifically stated within a section of this document or as the context may otherwise provide or indicate.

In addition, the following terms are commonly used throughout this document and have the meaning set forth below:

“amended and restated certificate of incorporation” means the Amended and Restated Certificate of Incorporation of Greenidge, as filed with the Secretary of State of Delaware on March 16, 2021.

“BTIG” means BTIG, LLC.

“bylaws” means the Amended and Restated Bylaws of Greenidge, as adopted on April 28, 2021.

“class A common stock” means the class A common stock, par value $0.0001 per share, of Greenidge.

“class B common stock” means the class B common stock, par value $0.0001 per share, of Greenidge.

“Closing” means the closing of the Merger.

“Closing Date” means the date of the Closing.

“Code” means the Internal Revenue Code of 1986, as amended from time to time.

“Controlling Stockholder” means Atlas Capital Resources (A9) LP.

“DGCL” means the General Corporation Law of the State of Delaware.

“Effective Time” means the date and time upon which the Merger is consummated by filing a certificate of merger with the Secretary of State of the State of Delaware relating to the Merger.

“Exchange Act” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

“GAAP” means United States generally accepted accounting principles.

“GGH LLC” means Greenidge Generation Holdings LLC, a Delaware limited liability company, together with its consolidated subsidiaries (which includes Greenidge Generation).

“Greenidge board” means the board of directors of Greenidge.

“Greenidge capital stock” means the class A common stock, the class B common stock and the series A preferred stock, in each case, of Greenidge.

“Greenidge common stock” means, collectively, the class A common stock and class B common stock of Greenidge.

“Greenidge Generation” means Greenidge Generation LLC, a New York limited liability company, alone, without inclusion of any of its parent or subsidiary entities whether before or after the Merger.

3

“Greenidge Issuances” means the issuance of (i) from and after consummation of the Merger, 562,174 shares of class A common stock to the Investor as a consulting fee in connection with the transactions contemplated by the Merger Agreement, (ii) from and after consummation of the Merger, options or warrants to purchase 344,800 shares of class A common stock at an exercise price of $6.25 per share of class A common stock to B. Riley Securities, Inc., (iii) 160,000 shares of class B common stock issued as consideration for bitcoin mining equipment, and (iv) all of the shares of Greenidge common stock underlying outstanding vested options reserved under the 2021 Plan.

“Greenidge stockholder” means each holder of Greenidge capital stock.

“Investment Company Act” means the Investment Company Act of 1940, as amended.

“Investor” means 210 Capital, LLC.

“Investor Fee” means 562,174 shares of class A common stock issuable to the Investor pursuant to the Merger Agreement.

“JOBS Act” means the Jumpstart Our Business Startups Act of 2012, as amended.

“Merger” means the merger of Merger Sub with and into Support with Support being the surviving entity.

“Merger Agreement” means that Agreement and Plan of Merger, dated as of the Signing Date, by and among Greenidge, Merger Sub and Support, as it may be amended from time to time.

“Merger Consideration” means 2,998,261 shares of class A common stock.

“Merger Sub” means GGH Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of Greenidge.

“Nasdaq” means the Nasdaq Capital Market.

“NYISO” means the New York Independent Systems Operator.

“Opinion” means the written opinion of BTIG attached to this proxy statement/prospectus as Annex D.

“Per Share Merger Consideration” means a number of shares of class A common stock equal to the Exchange Ratio.

“Securities Act” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

“series A preferred stock” means the series A preferred stock, par value $0.0001 per share, of Greenidge.

“Signing Date” means March 19, 2021.

“special meeting” means the special meeting of the Support stockholders to consider and vote upon the Merger Proposal, the Advisory Proposal and the Adjournment Proposal.

“Support awards” means any and all restricted stock units of Support and any other securities, rights or instruments of Support that are or could be convertible or exchangeable for Support common stock or otherwise could result in the issuance of Support common stock (whether or not upon the occurrence of any trigger or event, the satisfaction of any condition or consideration or otherwise, including with respect to the passage of time, that may otherwise be required with respect thereto), but which are not issuable upon payment of an exercise price, whether cashless or otherwise (or similar mechanic); provided, however, that the term “Support award” shall not include Support options.

“Support board” means the board of directors of Support.

“Support common stock” means the common stock, par value $0.0001 per share, of Support.

4

“Support options” means an option to purchase shares of Support common stock and any other securities, rights or instruments of Support that are or could be convertible or exchangeable for Support common stock or otherwise could result in the issuance of Support common stock, but which are issuable upon payment of an exercise price, whether cashless or otherwise (or similar mechanic).

“Support stockholder” means each holder of Support common stock.

“Termination Date” means December 22, 2021.

“VWAP” means the volume weighted average trading price per share of Support common stock for the ten-trading day period ending on and including the second business day immediately preceding the Closing Date.

5

QUESTIONS AND ANSWERS ABOUT THE MERGER AND THE SPECIAL MEETING

The following are some questions that you, as a stockholder of Support, may have regarding the special meeting of stockholders and the matters to be considered at the special meeting, as well as brief answers to those questions. You are urged to read carefully this entire proxy statement/prospectus, including the annexes included with the proxy statement/prospectus and the other documents incorporated by reference herein. See “Where You Can Find More Information.”

Support is holding a special meeting of stockholders in order to, among other things, obtain the stockholder approval necessary to adopt the Merger Agreement. The adoption of the Merger Agreement requires the affirmative vote of a majority of the issued and outstanding shares of Support common stock entitled to vote thereon. It is important that stockholders vote their shares on this matter, regardless of the number of shares owned.

This document is being delivered to you as both a proxy statement and a prospectus in connection with the Merger. It is the proxy statement by which Support’s board of directors is soliciting proxies from Support stockholders to vote at the special meeting, or at any adjournment or postponement of the special meeting. In addition, this document is the prospectus of Greenidge pursuant to which it will issue class A common stock to the Support stockholders as Merger Consideration in connection with the Merger.

6

In connection with the execution of the Merger Agreement, the Investor and all directors and certain executive officers of Support entered into a voting support agreement with Greenidge as of the Signing Date (the “Voting Agreement”), pursuant to which they have agreed to vote all of the shares of Support common stock that they beneficially own to approve the Merger Proposal, the Advisory Proposal and the Adjournment Proposal at the special meeting and have granted Greenidge their irrevocable proxy to vote such shares in such manner if they fail to perform their obligations under the Voting Agreement. As of the record date, the outstanding shares of Support common stock subject to the Voting Agreement represent approximately [            ] of the Support common stock as of that date.

Please carefully consider the information contained in this proxy statement/prospectus. Whether or not you plan to attend the special meeting, you are encouraged to vote via the Internet, by telephone or by mail so that your shares will be voted in accordance with your wishes even if you later decide to attend the special meeting. If you attend the special meeting, you may also vote in person, in which case any votes that you previously submitted—whether via the Internet, by telephone or by mail—will be revoked and superseded by the vote that you cast at the special meeting.

7

Your bank, brokerage firm or other nominee will not automatically vote your shares for you. Such entities typically have the authority to vote in their discretion on “routine” proposals when they have not received instructions on how to vote from the beneficial owner. However, banks, brokers and other nominee holders of record typically are not allowed to exercise their voting discretion on matters that are “non-routine” without specific instructions on how to vote from the beneficial owner. Each of the proposals to be considered at the special meeting as described in this proxy statement/prospectus are considered non-routine. Therefore banks, brokers, and other nominee holders of record do not have discretionary authority to vote on any of these proposals.

Broker non-votes are shares held by a bank, broker or other nominee holder of record that are present in person or represented by proxy at the special meeting, but with respect to which the bank, broker or other nominee holder of record is not instructed by the beneficial owner of such shares on how to vote on a particular proposal and does not have discretionary voting power on such proposal. Because, as mentioned above, banks, brokers and other nominee holders of record do not have discretionary voting authority with respect to any of the proposals to be considered at the special meeting as described in this proxy statement/prospectus, if a beneficial owner of shares held in “street name” does not give voting instructions to the broker, bank or other nominee holder of record, then those shares will not be present in person or represented by proxy at the special meeting and will not count for purposes of determining if a quorum is present at the special meeting. As a result, there will not be any broker non-votes in connection with the proposals to be considered at the special meeting as described in this proxy statement/prospectus.

You are not able to vote at the special meeting unless you have a proxy, executed in your favor, from the stockholder of record (bank, brokerage firm or other nominee) giving you the right to vote the shares. To vote in person at the special meeting, you will need to contact your bank, brokerage firm or other nominee holder of record to obtain a written legal proxy to bring to the meeting.

If you are a stockholder of record at the record date for the special meeting, you can revoke your proxy or change your vote by:

If you hold your shares in “street name” through a broker, bank or other nominee holder of record, you must contact your brokerage firm, bank or other nominee holder of record to change your vote or obtain a written legal proxy to vote your shares if you wish to cast your vote in person at the special meeting.

8

9

For additional information, see the section “Proposal I: The Merger—Reasons for the Merger”.

At the Effective Time of the Merger and subject to the terms and conditions set forth in the Merger Agreement, except for shares held in treasury by Support, each share of Support common stock that is issued and outstanding will be cancelled and automatically converted into the right to receive a number of shares of class A common stock equal to the Exchange Ratio.

Subject to the terms of the Merger Agreement, the Exchange Ratio is a fraction, expressed as a decimal rounded to the nearest one-thousandth, equal to the quotient of (i) 2,998,261 shares of class A common stock divided by (ii) the fully diluted number of outstanding shares of Support common stock as calculated pursuant to the Merger Agreement. Under the Merger Agreement, such fully diluted amount shall be the sum of (a) the total number of shares of capital stock of Support outstanding as of immediately prior to the Effective Time plus (b) the total number of shares of Support common stock underlying all Support awards outstanding as of the close of business on the second business day immediately preceding the Closing Date plus (c) the total number of shares of Support common stock underlying all Support options outstanding as of the close of business on the second business day immediately preceding the Closing Date, based on a treasury method share calculation using the volume weighted average trading price per share of Support common stock for the ten trading day period ending on and including the second business day immediately preceding the Closing Date (i.e., the VWAP).

The table below shows illustrative Exchange Ratios at various assumed VWAPs and assumes there are outstanding 24,237,876 shares of Support common stock, 130,507 Support awards and 1,690,615 shares of Support common stock underlying all Support options with an average exercise price of $1.68. In the table below, $2.14 is the closing sale price per share of Support’s common stock on March 19, 2021, the last trading day prior to the date of public announcement of the execution of the Merger Agreement, and $[        ] is the VWAP for the ten-trading day period ending on [                    ].

The calculation of the final Exchange Ratio will be determined in accordance with the formulas set forth in the Merger Agreement and announced immediately prior to the Closing.

10

The class A common stock of Greenidge that Support stockholders will receive in the Merger will have the same economic terms as the class B common stock of Greenidge, but the shares of class A common stock will have one vote per share in any matters on which Greenidge shareholders are entitled to vote generally and the shares of class B common stock will have ten votes per share in any matters on which Greenidge shareholders are entitled to vote generally.

Support provides customer and technical support solutions delivered by homebased employees. It is expected that the Support business will continue to operate as a wholly-owned subsidiary of Greenidge.

If the Merger is not completed, and depending on the circumstances that would have caused the Merger not to be completed, the price of Support’s common stock may decline significantly and Support may experience a negative impact on its business. If that were to occur, it is uncertain when, if ever, the price of Support’s common stock would return to the price at which it trades as of the date of this proxy statement/prospectus. Accordingly, if the Merger is not completed, there can be no assurance as to the effect of these risks and opportunities on the future value of shares of Support common stock.

If the Merger Agreement is terminated under specified circumstances, Support may be required to pay Greenidge a termination fee of up to $3.5 million or otherwise reimburse Greenidge’s fees and expenses of up to $2.0 million. For more information, see “The Merger Agreement—Termination Fees and Expenses” below.

In addition, if the Merger is not consummated, then the Investor will have certain rights to elect or appoint individuals to the Support board of directors, as more fully described below under “The Subscription Agreement”. Upon the earlier of December 31, 2021 or thirty days following the termination of the Merger Agreement, the Investor will have certain registration rights with respect to the Purchased Shares, as more fully described below under “The Subscription Agreement”.

11

Harkins Kovler, LLC

3 Columbus Circle, 15FL

New York, NY 10019

Toll: +1 (212) 468-5380

Toll Free: +1 (800) 326-5997

Email: SPRT@harkinskovler.com

12

13

14

15

16

17

18

19

20

21

22

SUMMARY CONSOLIDATED FINANCIAL DATA OF SUPPORT

The following tables present summary historical consolidated financial data of Support. The summary historical consolidated financial data of Support as of December 31, 2020 and for the years ended December 31, 2020 and December 31, 2019 have been derived from the audited consolidated financial statements of Support contained in its Annual Report on Form 10-K/A for the year ended December 31, 2020 incorporated by reference into this proxy statement/prospectus. The summary historical consolidated financial data of Support as of March 31, 2021 and for the three months ended March 31, 2021 and March 31, 2020 have been derived from the unaudited consolidated financial statements of Support contained in its Quarterly Report on Form 10-Q for the quarter ended March 31, 2021 incorporated by reference into this proxy statement/prospectus.

The summary historical consolidated financial data is only a summary and should be read together with, and is qualified in its entirety by reference to, Support’s “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and the financial statements and notes thereto incorporated by reference into this proxy statement/prospectus. See “Where You Can Find More Information.”

Statement of Operations Data (in thousands except per share amounts):

Selected Balance Sheet Data (in thousands):

23

SUMMARY CONSOLIDATED FINANCIAL DATA OF GREENIDGE

The following tables present summary historical consolidated financial data of Greenidge. The summary historical consolidated financial data should be read in conjunction with the financial statements and related notes of Greenidge contained elsewhere in this proxy statement/prospectus and the information under “Management’s Discussion and Analysis of Financial Condition and Results of Operations for Greenidge.”

The summary financial data as of December 31, 2020 and 2019 and for the years then ended are derived from the audited consolidated financial statements of Greenidge contained elsewhere in this proxy statement/prospectus. The summary financial data as of March 31, 2021 and for the three months ended March 31, 2021 and March 31, 2020 are derived from the unaudited consolidated financial statements of Greenidge contained elsewhere in this proxy statement/prospectus. Greenidge’s financial statements are prepared and presented in accordance with U.S. GAAP.

The summary financial data is only a summary and should be read in conjunction with the historical financial statements and related notes. Greenidge is the successor entity for accounting purposes to GGH LLC as a result of the corporate restructuring consummated in January 2021.

Pursuant to this restructuring, Greenidge was incorporated in the State of Delaware on January 27, 2021 and, on January 29, 2021, it entered into an asset contribution and exchange agreement with all holders of GGH LLC, pursuant to which Greenidge acquired all of the ownership interests in GGH LLC in exchange for 7,000,000 shares of Greenidge’s common stock. As a result of this transaction, GGH LLC became a wholly-owned subsidiary of Greenidge. The financial information presented herein is that of GGH LLC through January 29, 2021 and Greenidge thereafter.

Statement of Operations Data (in thousands except per share amounts):

Selected Balance Sheet Data (in thousands):

24

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

The following unaudited pro forma condensed combined financial information was prepared using the acquisition method of accounting under U.S. GAAP, and gives effect to the transaction between Greenidge and Support to be accounted for as a business combination, with Greenidge being deemed the acquiring company for accounting purposes.

Greenidge was determined to be the accounting acquirer based upon the terms of the Merger Agreement and other factors including: (i) Greenidge stockholders are expected to own approximately 90% of the fully-diluted Greenidge common stock immediately following the closing of the transaction; (ii) the largest individual stockholder of the combined entity is an existing stockholder of Greenidge; (iii) directors appointed by Greenidge will hold a majority of board seats of the combined company; and (iv) Greenidge’s senior management will be the senior management of Greenidge following consummation of the Merger.

The following unaudited pro forma condensed combined financial statements are based on Greenidge’s historical financial statements and Support’s historical financial statements, as adjusted to give effect to Greenidge’s acquisition of Support and certain related transactions. The unaudited pro forma condensed combined statement of operations for the quarter ended March 31, 2021 and the year ended December 31, 2020 gives effect to these transactions as if they had occurred on January 1, 2020. The unaudited pro forma condensed combined balance sheet as of March 31, 2021 gives effect to these transactions as if they had occurred on March 31, 2021.

Because Greenidge will be treated as the accounting acquirer, Greenidge’s assets and liabilities will be recorded at their pre-combination carrying amounts and the historical operations that are reflected in the unaudited pro forma financial information will be those of Greenidge. Support’s assets and liabilities will be measured and recognized at their fair values as of the transaction date, and combined with the assets, liabilities and results of operations of Greenidge after the consummation of the transaction.

The unaudited pro forma condensed combined financial information is based on the assumptions and adjustments that are described in the accompanying notes. The application of the acquisition method of accounting is dependent upon a purchase price allocation analysis, which includes valuation analysis and other studies that have yet to be completed, pursuant to Financial Accounting Standards Board Accounting Standards Codification Topic 805, Business Combinations. Accordingly, the pro forma adjustments are preliminary, subject to further revision as additional information becomes available and additional analyses are performed, and have been made solely for the purpose of providing unaudited pro forma condensed combined financial information. Differences between these preliminary estimates and the final acquisition accounting, expected to be completed after the closing of the transaction, will occur and these differences could have a material impact on the accompanying unaudited pro forma condensed combined financial information and the combined company’s future results of operations and financial position. In addition, differences between the preliminary and final amounts will likely occur as a result of changes in the fair value of Support’s common stock and changes in Support’s assets and liabilities.

The unaudited pro forma condensed combined financial information does not give effect to the potential impact of current financial conditions, regulatory matters, operating efficiencies or other savings or expenses that may be associated with the integration of the two companies. The unaudited pro forma condensed combined financial information is preliminary and has been prepared for illustrative purposes only and is not necessarily indicative of the financial position or results of operations in future periods or the results that actually would have been realized had Greenidge and Support been a combined company during the specified periods. The actual results reported in periods following the transaction may differ significantly from those reflected in these pro forma financial information presented herein for a number of reasons, including, but not limited to, differences between the assumptions used to prepare this pro forma financial information and actual results realized.

The assumptions and estimates underlying the unaudited adjustments to the pro forma condensed combined financial statements are described in the accompanying notes, which should be read together with the pro forma condensed combined financial statements.

25

Pro Forma Condensed Combined Balance Sheet as of March 31, 2021

(in thousands)

26

Pro Forma Condensed Combined Statement of Operations—Quarter Ended March 31, 2021

(in thousands, except per share amounts)

Pro Forma Condensed Combined Statement of Operations—Year Ended December 31, 2020

(in thousands, except per share amounts)