The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, dated April 29, 2022

PROSPECTUS

Ouster, Inc.

$250,000,000

Common Stock

Preferred Stock

Debt Securities

Depositary Shares

Warrants

Purchase Contracts

Units

We may offer and sell up to $250,000,000 in the aggregate of the securities identified above from time to time in one or more offerings. This prospectus provides you with a general description of the securities.

Each time we offer and sell securities, we will provide a supplement to this prospectus that contains specific information about the offering and the amounts, prices and terms of the securities. The supplement may also add, update or change information contained in this prospectus with respect to that offering. You should carefully read this prospectus and the applicable prospectus supplement before you invest in any of our securities.

We may offer and sell the securities described in this prospectus and any prospectus supplement to or through one or more underwriters, dealers and agents, or directly to purchasers, or through a combination of these methods. If any underwriters, dealers or agents are involved in the sale of any of the securities, their names and any applicable purchase price, fee, commission or discount arrangement between or among them will be set forth, or will be calculable from the information set forth, in the applicable prospectus supplement to the extent appropriate or required by law. See the sections of this prospectus entitled “About This Prospectus” and “Plan of Distribution” for more information. No securities may be sold without delivery of this prospectus and the applicable prospectus supplement describing the method and terms of the offering of such securities.

INVESTING IN OUR SECURITIES INVOLVES RISKS. SEE THE “RISK FACTORS” ON PAGE 5 OF THIS PROSPECTUS AND ANY SIMILAR SECTION CONTAINED IN THE APPLICABLE PROSPECTUS SUPPLEMENT AND IN THE DOCUMENTS INCORPORATED BY REFERENCE HEREIN OR THEREIN CONCERNING FACTORS YOU SHOULD CONSIDER BEFORE INVESTING IN OUR SECURITIES.

Our common stock trades on the New York Stock Exchange (the “NYSE”) under the ticker symbol “OUST” and our warrants trade on the NYSE under the ticker symbol “OUST WS”. On April 28, 2022, the closing sale price of our common stock as reported by the NYSE was $3.40 per share and the closing price of our warrants was $0.70 per warrant.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is                 , 2022.

TABLE OF CONTENTS

i

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the U.S. Securities and Exchange Commission (the “SEC”) using a “shelf” registration process. By using a shelf registration statement, we may sell securities from time to time and in one or more offerings as described in this prospectus. Each time that we offer and sell securities, we will provide a prospectus supplement to this prospectus that contains specific information about the securities being offered and sold and the specific terms of that offering. To the extent permitted by law, we may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. Such prospectus supplement or free writing prospectus may also add, update or change information contained in this prospectus with respect to that offering. If there is any inconsistency between the information in this prospectus and the applicable prospectus supplement or free writing prospectus, you should rely on the prospectus supplement or free writing prospectus, as applicable. Before purchasing any securities, you should carefully read both this prospectus and the applicable prospectus supplement (and any applicable free writing prospectuses), together with the additional information described under the heading “Where You Can Find More Information; Incorporation by Reference.”

We have not authorized anyone to provide you with any information or to make any representations other than those contained in this prospectus, any applicable prospectus supplement or any free writing prospectuses prepared by or on behalf of us or to which we have referred you. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus and the applicable prospectus supplement to this prospectus is accurate only as of the date on its respective cover, that the information appearing in any applicable free writing prospectus is accurate only as of the date of that free writing prospectus, and that any information incorporated by reference is accurate only as of the date of the document incorporated by reference or, in each case, any earlier date specified for such information, unless we indicate otherwise. Our business, financial condition, results of operations and prospects may have changed since those dates. This prospectus incorporates by reference, and any prospectus supplement or free writing prospectus may contain and incorporate by reference, market data and industry statistics and forecasts that are based on independent industry publications and other publicly available information. Although we believe these sources are reliable, we do not guarantee the accuracy or completeness of this information and we have not independently verified this information. In addition, the market and industry data and forecasts that may be included or incorporated by reference in this prospectus, any prospectus supplement or any applicable free writing prospectus may involve estimates, assumptions and other risks and uncertainties and are subject to change based on various factors, including those discussed under the heading “Risk Factors” contained in this prospectus, the applicable prospectus supplement and any applicable free writing prospectus, and under similar headings in other documents that are incorporated by reference into this prospectus. Accordingly, investors should not place undue reliance on this information.

When we refer to “we,” “our,” “us” and the “Company” in this prospectus, we mean Ouster, Inc. and its consolidated subsidiaries, unless otherwise specified. When we refer to “you,” we mean the potential holders of the applicable series of securities.

WHERE YOU CAN FIND MORE INFORMATION;

INCORPORATION BY REFERENCE

Available Information

We file reports, proxy statements and other information with the SEC. The SEC maintains a web site that contains reports, proxy and information statements and other information about issuers, such as us, who file electronically with the SEC. The address of that website is http://www.sec.gov. You may access these materials free of charge as soon as reasonably practicable after they are electronically filed with or furnished to the SEC.

Our web site address is www.ouster.com. The information on our web site, however, is not, and should not be deemed to be, a part of, or incorporated by reference into, this prospectus.

This prospectus and any prospectus supplement are part of a registration statement that we filed with the SEC and do not contain all of the information in the registration statement. The full registration statement may be obtained from the SEC or us, as provided above. Forms of the indenture and other documents establishing the terms of any offered securities are or may be filed as exhibits to the registration statement or documents incorporated by reference in the registration statement. Statements in this prospectus or any prospectus supplement about these documents are summaries and each statement is qualified in all respects by reference to the document to which it refers. You should refer to the actual documents for a more complete description of the relevant matters. You may inspect a copy of the registration statement through the SEC’s website, as provided above.

Incorporation by Reference

The SEC’s rules allow us to “incorporate by reference” information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus, and subsequent information that we file with the SEC will automatically update and supersede that information. Any statement contained in this prospectus or a previously filed document incorporated by reference will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or a subsequently filed document incorporated by reference modifies or replaces that statement.

This prospectus and any accompanying prospectus supplement incorporate by reference the documents set forth below that have previously been filed with the SEC:

All reports and other documents we subsequently file pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, which we refer to as the “Exchange Act” in this prospectus, prior to the termination of this offering, including all such documents we may file with the SEC after the date of the initial registration statement and prior to the effectiveness of the registration statement, but excluding any information furnished to, rather than filed with, the SEC, will also be incorporated by reference into this prospectus and deemed to be part of this prospectus from the date of the filing of such reports and documents.

You may request a free copy of any of the documents incorporated by reference in this prospectus by writing or telephoning us at the following address:

Ouster, Inc.

350 Treat Avenue

San Francisco, California 94110

(415) 949-0108

Exhibits to the filings will not be sent, however, unless those exhibits have specifically been incorporated by reference in this prospectus or any accompanying prospectus supplement.

THE COMPANY

Ouster is building the eyes of autonomy. We are a leading provider of high-resolution digital lidar sensors and enabling software that gives robots, machinery, vehicles and fixed infrastructure advanced 3D vision allowing them to safely interact with the physical world.

We design and manufacture digital lidar sensors that we believe to be the highest performing, lowest cost lidar solutions available today across each of our four target markets: automotive, industrial automation; smart infrastructure and robotics. We believe that our digital lidar technology positions us at the center of a global revolution in autonomy. We believe that 3D vision technologies, coupled with artificial intelligence, will power new autonomous technologies that in turn will fundamentally disrupt business models across many existing industries and also enable entirely new industries and capabilities.

Beyond the automotive market, we believe that there is an even larger market for lidar sensors. We believe our highly flexible digital lidar architecture strongly positions us to address what we believe is a rapidly growing demand. Our industrial customers today are using lidar to increase safety and automating operations across the global supply chain, in material handling vehicles at ports and warehouses, in off-highway vehicles at mines and farms, and in manufacturing equipment in factories. In our smart infrastructure vertical, cities are increasing safety and efficiency through using lidar control traffic lights and warning systems, and security companies are improving intrusion detection and tracking by augmenting existing CCTV systems with the spatial tracking capabilities of lidar. We believe these markets present a significant opportunity for growth, as they touch nearly every aspect of our daily lives.

We envision a future where lidar-powered solutions are widespread, with useful and affordable 3D perception capabilities built into every moving robot, car, truck and drone, as well as every factory, building, stoplight, dock, and airport terminal.

The registrant was initially incorporated under the name “Colonnade Acquisition Corp.” on June 4, 2020 as a Cayman Islands exempted company for purposes of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses. On March 10, 2021, the registrant domesticated into a Delaware corporation and changed our name to “Ouster, Inc.” in connection with the consummation of the business combination with Ouster Technologies, Inc. Following the business combination, the operations of Ouster Technologies, Inc. were the only ongoing operations of the registrant.

Our principal executive office is located at 350 Treat Avenue, San Francisco, CA 94110. Our telephone number is (415) 949-0108. Our website address is www.ouster.com. Information contained on our website is not a part of this prospectus, and the inclusion of our website address in this prospectus is an inactive textual reference only.

RISK FACTORS

Investment in any securities offered pursuant to this prospectus and the applicable prospectus supplement involves risks. You should carefully consider the risk factors incorporated by reference to our most recent Annual Report on Form 10-K, and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and all other information contained or incorporated by reference into this prospectus, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in the applicable prospectus supplement and any applicable free writing prospectus before acquiring any of such securities. The risks and uncertainties we have described are not the only ones facing our company. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business operations. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities. The discussion of risks includes or refers to forward-looking statements. You should read the explanation of the qualifications and limitations on such forward-looking statements contained or incorporated by reference into this prospectus and in any applicable prospectus supplement.

USE OF PROCEEDS

We intend to use the net proceeds from the sale of the securities as set forth in the applicable prospectus supplement.

DESCRIPTION OF CAPITAL STOCK

The following description of the terms of our capital stock and warrants is not complete and is qualified in its entirety by reference to our Restated Certificate of Incorporation, as amended (the “Certificate of Incorporation”), our Amended and Restated Bylaws (the “Bylaws”) and the warrant agreement, all of which are attached as exhibits to our Annual Report on Form 10-K.

Capital Stock

Authorized Capitalization

General

The total amount of our authorized capital stock consists of 1,000,000,000 shares of common stock, par value $0.0001 per share, and 100,000,000 shares of preferred stock, par value $0.0001 per share.

Preferred Stock

Our board of directors (the “Board”) has authority to issue shares of preferred stock in one or more series, to fix for each such series such voting powers, designations, preferences, qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, redemption privileges and liquidation preferences for the issue of such series all to the fullest extent permitted by the Delaware General Corporation Law (“DGCL”). The issuance of preferred stock could have the effect of decreasing the trading price of our common stock, restricting dividends on our capital stock, diluting the voting power of our common stock, impairing the liquidation rights of our capital stock, or delaying or preventing a change in control of our company.

We will fix the designations, voting powers, preferences and rights of the preferred stock of each series, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of that series of preferred stock. This description will include all of the terms:

The DGCL provides that the holders of preferred stock will have the right to vote separately as a class (or, in some cases, as a series) on an amendment to our certificate of incorporation if the amendment would change the par value or, unless the certificate of incorporation provided otherwise, the number of authorized shares of the class or change the powers, preferences or special rights of the class or series so as to adversely affect the class or series, as the case may be. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.

Common Stock

Our common stock does not entitle its holders to preemptive or other similar subscription rights to purchase any of our securities. Our common stock is neither convertible nor redeemable. Unless our Board determines otherwise, we will issue all of our capital stock in uncertificated form.

Voting Rights

Each holder of our common stock is entitled to one vote per share on each matter submitted to a vote of stockholders, as provided by the Certificate of Incorporation. The Bylaws provide that the holders of a majority of the capital stock issued and outstanding and entitled to vote thereat, present in person, or by remote communication, if applicable, or represented by proxy, will constitute a quorum at all meetings of the stockholders for the transaction of business. When a quorum is present, the affirmative vote of a majority of the

votes cast is required to take action, unless otherwise specified by law, the Bylaws or the Certificate of Incorporation, and except for the election of directors, which is determined by a plurality vote. There are no cumulative voting rights.

Dividend Rights

Each holder of shares of our capital stock is entitled to the payment of dividends and other distributions as may be declared by Board from time to time out of our assets or funds legally available for dividends or other distributions. These rights are subject to the preferential rights of the holders of our preferred stock, if any, and any contractual limitations on our ability to declare and pay dividends.

Other Rights

The rights of each holder of our common stock are subject to, and may be adversely affected by, the rights of the holders of any series of our preferred stock that we may designate and issue in the future.

Liquidation Rights

If we are involved in voluntary or involuntary liquidation, dissolution or winding up of our affairs, or a similar event, each holder of our common stock will participate pro rata in all assets remaining after payment of liabilities, subject to prior distribution rights of our preferred stock, if any, then outstanding.

Anti-takeover Effects of the Certificate of Incorporation and the Bylaws

The Certificate of Incorporation and the Bylaws contain provisions that may delay, defer or discourage another party from acquiring control of our company. We expect that these provisions, which are summarized below, will discourage coercive takeover practices or inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of our company to first negotiate with the Board, which we believe may result in an improvement of the terms of any such acquisition in favor of our stockholders. However, they also give the Board the power to discourage mergers that some stockholders may favor.

Special Meetings of Stockholders

The Certificate of Incorporation provides that a special meeting of stockholders may be called by (a) the Chairperson of the Board, (b) the Board, (c) our Chief Executive Officer or (d) our President, provided that such special meeting may be postponed, rescheduled or cancelled by the Board or other person calling the special meeting.

Action by Written Consent

The Certificate of Incorporation provides that any action required or permitted to be taken by our stockholders must be effected at an annual or special meeting of the stockholders, and may not be taken by written consent in lieu of a meeting.

Classified Board of Directors

Our Certificate of Incorporation provides that our Board is divided into three classes, with the classes as nearly equal in number as possible and each class serving three-year staggered terms. The Board or any individual director may be removed from office at any time, but only for cause and only by the affirmative vote of the holders of at least a majority of the voting power of all of the then outstanding shares of our voting stock entitled to vote at an election of directors.

Election of Directors and Vacancies

Subject to the rights of the holders of any series of preferred stock to elect additional directors under specified circumstances, the number of directors of our Board is fixed exclusively by the Board. Our Board is divided into three classes, designated Class I, II and III, with each class to be elected by our stockholders every three years.

Amendment of the Certificate of Incorporation and Bylaws

Our Board is expressly authorized to adopt, amend or repeal the Bylaws, subject to the power of our stockholders entitled to vote with respect thereto to adopt, amend or repeal the Bylaws. Our stockholders have the power to adopt, amend or repeal the Bylaws; provided, that in addition to any vote of the holders of any class or series of our stock required by applicable law or by our Certificate of Incorporation or Bylaws, the adoption, amendment or repeal of our Bylaws by our stockholders shall require the affirmative vote of the holders of at least two-thirds of the voting power of all of the then outstanding shares of our voting stock entitled to vote generally in an election of directors.

Additionally, the vote of at least 66 2/3% of the total voting power of our outstanding shares entitled to vote thereon, voting together as a single class, is required to amend certain provisions of our Certificate of Incorporation, including those relating to the terms of our authorized preferred stock (Article V(B)), the authority and composition of our Board (Article VII), special meetings of our stockholders and the ability of our stockholders to act by written consent (Article VIII), limitation of liability of our directors (Article IX), restrictions similar to Section 203 of the DGCL (Article X), our obligation to indemnify our directors and officers to the fullest extent permitted by law (Article XI), exclusive jurisdiction of certain legal proceedings involving our stockholders (Article XII).

Delaware Anti-Takeover Statute

Section 203 of the DGCL provides that if a person acquires 15% or more of the voting stock of a Delaware corporation, such person becomes an “interested stockholder” and may not engage in certain “business combinations” with such corporation for a period of three years from the time such person acquired 15% or more of such corporation’s voting stock, unless: (a) the board of directors of such corporation approves the acquisition of stock or the merger transaction before the time that the person becomes an interested stockholder, (b) the interested stockholder owns at least 85% of the outstanding voting stock of such corporation at the time the merger transaction commences (excluding voting stock owned by directors who are also officers and certain employee stock plans), or (c) the merger transaction is approved by the board of directors and at a meeting of stockholders, not by written consent, by the affirmative vote of at least two-thirds of the outstanding voting stock which is not owned by the interested stockholder. A Delaware corporation may elect in its certificate of incorporation or bylaws not to be governed by this particular Delaware law. Under the Certificate of Incorporation, we have opted out of Section 203 of the DGCL, but the Certificate of Incorporation provides other similar restrictions regarding takeovers by interested stockholders.

Limitations on Liability and Indemnification of Officers and Directors

The Certificate of Incorporation provides that we are to indemnify our directors to the fullest extent authorized or permitted by applicable law. We have entered and expect to continue to enter into agreements to indemnify our directors, executive officers and other employees as determined by the Board. Under the Bylaws, we are required to indemnify each of our directors and officers if the basis of the indemnitee’s involvement was by reason of the fact that the indemnitee is or was our director or officer or was serving at our request as a director, officer, employee or agent for another entity. We must indemnify our officers and directors against all expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by the indemnitee in connection with such action, suit or proceeding if the indemnitee acted in good

faith and in a manner the indemnitee reasonably believed to be in or not opposed to our best interests, and, with respect to any criminal action or proceeding, had no reasonable cause to believe the indemnitee’s conduct was unlawful. The Bylaws also require us to advance expenses (including attorneys’ fees) incurred by a director or officer in defending any civil, criminal, administrative or investigative action, suit or proceeding, provided that such person will repay any such advance if it is ultimately determined that such person is not entitled to indemnification by us. Any claims for indemnification by our directors and officers may reduce our available funds to satisfy successful third-party claims against us and may reduce the amount of money available to us.

Exclusive Jurisdiction of Certain Actions

Our Certificate of Incorporation provides that, to the fullest extent permitted by law, and unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware (or, in the event that the Chancery Court does not have jurisdiction, the federal district court for the District of Delaware or other state courts of the State of Delaware) will be the sole and exclusive forum for (i) any derivative action, suit or proceeding brought on our behalf, (ii) any action, suit or proceeding asserting a claim of breach of a fiduciary duty owed by any of our directors, officers or stockholders to us or our stockholders, (iii) any action, suit or proceeding arising pursuant to any provision of the DGCL or the Bylaws or the Certificate of Incorporation (as each may be amended from time to time), (iv) any action, suit or proceeding as to which the DGCL confers jurisdiction on the Court of Chancery of the State of Delaware, or (v) any action, suit or proceeding asserting a claim against us or any current or former director, officer or stockholder governed by the internal affairs doctrine, and, if brought outside of Delaware, the stockholder bringing the suit will be deemed to have consented to (a) the personal jurisdiction of the state and federal courts in the State of Delaware in connection with any action brought in any such court to enforce the exclusive jurisdiction provisions of the Certificate of Incorporation and (b) service of process on such stockholder’s counsel.

Section 22 of the Securities Act creates concurrent jurisdiction for federal and state courts over all suits brought to enforce any duty or liability created by the Securities Act or the rules and regulations thereunder. Accordingly, both state and federal courts have jurisdiction to entertain such Securities Act claims. To prevent having to litigate claims in multiple jurisdictions and the threat of inconsistent or contrary rulings by different courts, among other considerations, the Certificate of Incorporation also provides that, unless we consent in writing to the selection of an alternative forum, to the fullest extent permitted by law, the federal district courts of the United States of America shall be the exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act; however, there is uncertainty as to whether a court would enforce such provision, and investors cannot waive compliance with federal securities laws and the rules and regulations thereunder. Notwithstanding the foregoing, the Certificate of Incorporation provides that the exclusive forum provision will not apply to suits brought to enforce any cause of action arising by the Exchange Act or any other claim for which the federal courts have exclusive jurisdiction. Section 27 of the Exchange Act creates exclusive federal jurisdiction over all suits brought to enforce any duty or liability created by the Exchange Act or the rules and regulations thereunder. Although we believe these provisions would benefit us by providing increased consistency in the application of applicable law in the types of lawsuits to which they apply, these provisions may have the effect of discouraging lawsuits against our directors and officers.

Transfer Agent

The transfer agent for our common stock is Continental Stock Transfer & Trust Company.

DESCRIPTION OF DEBT SECURITIES

The following description, together with the additional information we include in any applicable prospectus supplement or free writing prospectus, summarizes certain general terms and provisions of the debt securities that we may offer under this prospectus. When we offer to sell a particular series of debt securities, we will describe the specific terms of the series in a supplement to this prospectus. We will also indicate in the supplement to what extent the general terms and provisions described in this prospectus apply to a particular series of debt securities. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below.

We may issue debt securities either separately, or together with, or upon the conversion or exercise of or in exchange for, other securities described in this prospectus. Debt securities may be our senior, senior subordinated or subordinated obligations and, unless otherwise specified in a supplement to this prospectus, the debt securities will be our direct, unsecured obligations and may be issued in one or more series.

The debt securities will be issued under an indenture between us and Wilmington Trust, National Association, as trustee. We have summarized select portions of the indenture below. The summary is not complete. The form of the indenture has been filed as an exhibit to the registration statement of which this prospectus forms a part and you should read the indenture for provisions that may be important to you. In the summary below, we have included references to the section numbers of the indenture so that you can easily locate these provisions. Capitalized terms used in the summary and not defined herein have the meanings specified in the indenture.

As used in this section only, “Ouster,” “we,” “our” or “us” refer to Ouster, Inc. excluding our subsidiaries, unless expressly stated or the context otherwise requires.

General

The terms of each series of debt securities will be established by or pursuant to a resolution of our board of directors and set forth or determined in the manner provided in a resolution of our board of directors, in an officer’s certificate or by a supplemental indenture. (Section 2.2) The particular terms of each series of debt securities will be described in a prospectus supplement relating to such series (including any pricing supplement or term sheet).

We can issue an unlimited amount of debt securities under the indenture that may be in one or more series with the same or various maturities, at par, at a premium, or at a discount. (Section 2.1) We will set forth in a prospectus supplement (including any pricing supplement or term sheet) relating to any series of debt securities being offered, the aggregate principal amount and the following terms of the debt securities, if applicable:

We may issue debt securities that provide for an amount less than their stated principal amount to be due and payable upon declaration of acceleration of their maturity pursuant to the terms of the indenture. We will provide you with information on the federal income tax considerations and other special considerations applicable to any of these debt securities in the applicable prospectus supplement.

If we denominate the purchase price of any of the debt securities in a foreign currency or currencies or a foreign currency unit or units, or if the principal of and any premium and interest on any series of debt securities is payable in a foreign currency or currencies or a foreign currency unit or units, we will provide you with information on the restrictions, elections, general tax considerations, specific terms and other information with respect to that issue of debt securities and such foreign currency or currencies or foreign currency unit or units in the applicable prospectus supplement.

Transfer and Exchange

Each debt security will be represented by either one or more global securities registered in the name of The Depository Trust Company, or the Depositary, or a nominee of the Depositary (we will refer to any debt security represented by a global debt security as a “book-entry debt security”), or a certificate issued in definitive registered form (we will refer to any debt security represented by a certificated security as a “certificated debt security”) as set forth in the applicable prospectus supplement. Except as set forth under the heading “Global Debt Securities and Book-Entry System” below, book-entry debt securities will not be issuable in certificated form.

Certificated Debt Securities. You may transfer or exchange certificated debt securities at any office we maintain for this purpose in accordance with the terms of the indenture. (Section 2.4) No service charge will be made for any transfer or exchange of certificated debt securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with a transfer or exchange. (Section 2.7)

You may effect the transfer of certificated debt securities and the right to receive the principal of, premium and interest on certificated debt securities only by surrendering the certificate representing those certificated debt securities and either reissuance by us or the trustee of the certificate to the new holder or the issuance by us or the trustee of a new certificate to the new holder.

Global Debt Securities and Book-Entry System. Each global debt security representing book-entry debt securities will be deposited with, or on behalf of, the Depositary, and registered in the name of the Depositary or a nominee of the Depositary. Please see “Global Securities.”

Covenants

We will set forth in the applicable prospectus supplement any restrictive covenants applicable to any issue of debt securities. (Article IV)

No Protection in the Event of a Change of Control

Unless we state otherwise in the applicable prospectus supplement, the debt securities will not contain any provisions which may afford holders of the debt securities protection in the event we have a change in control or in the event of a highly leveraged transaction (whether or not such transaction results in a change in control) which could adversely affect holders of debt securities.

Consolidation, Merger and Sale of Assets

We may not consolidate with or merge with or into, or convey, transfer or lease all or substantially all of our properties and assets to any person (a “successor person”) unless:

Notwithstanding the above, any of our subsidiaries may consolidate with, merge into or transfer all or part of its properties to us. (Section 5.1)

Events of Default

“Event of Default” means with respect to any series of debt securities, any of the following:

No Event of Default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an Event of Default with respect to any other series of debt securities. (Section 6.1) The occurrence of certain Events of Default or an acceleration under the indenture may constitute an event of default under certain indebtedness of ours or our subsidiaries outstanding from time to time.

We will provide the trustee written notice of any Default or Event of Default within 30 days of becoming aware of the occurrence of such Default or Event of Default, which notice will describe in reasonable detail the status of such Default or Event of Default and what action we are taking or propose to take in respect thereof. (Section 6.1)

If an Event of Default with respect to debt securities of any series at the time outstanding occurs and is continuing, then the trustee or the holders of not less than 25% in principal amount of the outstanding debt securities of that series may, by a notice in writing to us (and to the trustee if given by the holders), declare to be due and payable immediately the principal of (or, if the debt securities of that series are discount securities, that portion of the principal amount as may be specified in the terms of that series) and accrued and unpaid interest, if any, on all debt securities of that series. In the case of an Event of Default resulting from certain events of bankruptcy, insolvency or reorganization, the principal (or such specified amount) of and accrued and unpaid

interest, if any, on all outstanding debt securities will become and be immediately due and payable without any declaration or other act on the part of the trustee or any holder of outstanding debt securities. At any time after a declaration of acceleration with respect to debt securities of any series has been made, but before a judgment or decree for payment of the money due has been obtained by the trustee, the holders of a majority in principal amount of the outstanding debt securities of that series may rescind and annul the acceleration if all Events of Default, other than the non-payment of accelerated principal and interest, if any, with respect to debt securities of that series, have been cured or waived as provided in the indenture. (Section 6.2) We refer you to the prospectus supplement relating to any series of debt securities that are discount securities for the particular provisions relating to acceleration of a portion of the principal amount of such discount securities upon the occurrence of an Event of Default.

The indenture provides that the trustee may refuse to perform any duty or exercise any of its rights or powers under the indenture unless the trustee receives indemnity satisfactory to it against any cost, liability or expense which might be incurred by it in performing such duty or exercising such right or power. (Section 7.1(e)) Subject to certain rights of the trustee, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee or exercising any trust or power conferred on the trustee with respect to the debt securities of that series. (Section 6.12)

No holder of any debt security of any series will have any right to institute any proceeding, judicial or otherwise, with respect to the indenture or for the appointment of a receiver or trustee, or for any remedy under the indenture, unless:

Notwithstanding any other provision in the indenture, the holder of any debt security will have an absolute and unconditional right to receive payment of the principal of, premium and any interest on that debt security on or after the due dates expressed in that debt security and to institute suit for the enforcement of payment. (Section 6.8)

The indenture requires us, within 120 days after the end of our fiscal year, to furnish to the trustee a statement as to compliance with the indenture. (Section 4.3) If a Default or Event of Default occurs and is continuing with respect to the securities of any series and if it is known to a responsible officer of the trustee, the trustee shall mail to each Securityholder of the securities of that series notice of a Default or Event of Default within 90 days after it occurs or, if later, after a responsible officer of the trustee has knowledge of such Default or Event of Default. The indenture provides that the trustee may withhold notice to the holders of debt securities of any series of any Default or Event of Default (except in payment on any debt securities of that series) with respect to debt securities of that series if the trustee determines in good faith that withholding notice is in the interest of the holders of those debt securities. (Section 7.5)

Modification and Waiver

We and the trustee may modify, amend or supplement the indenture or the debt securities of any series without the consent of any holder of any debt security:

We may also modify and amend the indenture with the consent of the holders of at least a majority in principal amount of the outstanding debt securities of each series affected by the modifications or amendments. We may not make any modification or amendment without the consent of the holders of each affected debt security then outstanding if that amendment will:

Except for certain specified provisions, the holders of at least a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all debt securities of that series waive our compliance with provisions of the indenture. (Section 9.2) The holders of a majority in principal amount of

the outstanding debt securities of any series may on behalf of the holders of all the debt securities of such series waive any past default under the indenture with respect to that series and its consequences, except a default in the payment of the principal of, premium or any interest on any debt security of that series; provided, however, that the holders of a majority in principal amount of the outstanding debt securities of any series may rescind an acceleration and its consequences, including any related payment default that resulted from the acceleration. (Section 6.13)

Defeasance of Debt Securities and Certain Covenants in Certain Circumstances

Legal Defeasance. The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, we may be discharged from any and all obligations in respect of the debt securities of any series (subject to certain exceptions). We will be so discharged upon the irrevocable deposit with the trustee, in trust, of money and/or U.S. government obligations or, in the case of debt securities denominated in a single currency other than U.S. Dollars, government obligations of the government that issued or caused to be issued such currency, that, through the payment of interest and principal in accordance with their terms, will provide money or U.S. government obligations in an amount sufficient in the opinion of a nationally recognized firm of independent public accountants or investment bank to pay and discharge each installment of principal, premium and interest on and any mandatory sinking fund payments in respect of the debt securities of that series on the stated maturity of those payments in accordance with the terms of the indenture and those debt securities.

This discharge may occur only if, among other things, we have delivered to the trustee an opinion of counsel stating that we have received from, or there has been published by, the United States Internal Revenue Service a ruling or, since the date of execution of the indenture, there has been a change in the applicable United States federal income tax law, in either case to the effect that, and based thereon such opinion shall confirm that, the holders of the debt securities of that series will not recognize income, gain or loss for United States federal income tax purposes as a result of the deposit, defeasance and discharge and will be subject to United States federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit, defeasance and discharge had not occurred. (Section 8.3)

Defeasance of Certain Covenants. The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, upon compliance with certain conditions:

The conditions include:

No Personal Liability of Directors, Officers, Employees or Securityholders

None of our past, present or future directors, officers, employees or securityholders, as such, will have any liability for any of our obligations under the debt securities or the indenture or for any claim based on, or in respect or by reason of, such obligations or their creation. By accepting a debt security, each holder waives and releases all such liability. This waiver and release is part of the consideration for the issue of the debt securities. However, this waiver and release may not be effective to waive liabilities under U.S. federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

Governing Law

The indenture and the debt securities, including any claim or controversy arising out of or relating to the indenture or the securities, will be governed by the laws of the State of New York.

The indenture will provide that we, the trustee and the holders of the debt securities (by their acceptance of the debt securities) irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to the indenture, the debt securities or the transactions contemplated thereby.

The indenture will provide that any legal suit, action or proceeding arising out of or based upon the indenture or the transactions contemplated thereby may be instituted in the federal courts of the United States of America located in the City of New York or the courts of the State of New York in each case located in the City of New York, and we, the trustee and the holder of the debt securities (by their acceptance of the debt securities) irrevocably submit to the non-exclusive jurisdiction of such courts in any such suit, action or proceeding. The indenture will further provide that service of any process, summons, notice or document by mail (to the extent allowed under any applicable statute or rule of court) to such party’s address set forth in the indenture will be effective service of process for any suit, action or other proceeding brought in any such court. The indenture will further provide that we, the trustee and the holders of the debt securities (by their acceptance of the debt securities) irrevocably and unconditionally waive any objection to the laying of venue of any suit, action or other proceeding in the courts specified above and irrevocably and unconditionally waive and agree not to plead or claim any such suit, action or other proceeding has been brought in an inconvenient forum. (Section 10.10)

DESCRIPTION OF DEPOSITARY SHARES

We may, at our option, elect to offer depositary shares rather than full shares of preferred stock. Each depositary share will represent ownership of and entitlement to all rights and preferences of a fraction of a share of preferred stock of a specified series (including dividend, voting, redemption and liquidation rights). The applicable fraction will be specified in a prospectus supplement. The shares of preferred stock represented by the depositary shares will be deposited with a depositary named in the applicable prospectus supplement, under a deposit agreement among us, the depositary and the holders of the certificates evidencing depositary shares, or depositary receipts. Depositary receipts will be delivered to those persons purchasing depositary shares in the offering. The depositary will be the transfer agent, registrar and dividend disbursing agent for the depositary shares. Holders of depositary receipts agree to be bound by the deposit agreement, which requires holders to take certain actions such as filing proof of residence and paying certain charges. The terms of any depositary shares offered under a prospectus supplement may differ from the terms described below. We urge you to read the applicable prospectus supplement and any related free writing prospectus, as well as the complete deposit agreement that contains the terms of the depositary shares.

The summary of the terms of the depositary shares contained in this prospectus does not purport to be complete and is subject to, and qualified in its entirety by, the provisions of the deposit agreement and our certificate of incorporation and the certificate of designation that are, or will be, filed with the SEC for the applicable series of preferred stock.

Dividends

The depositary will distribute all cash dividends or other cash distributions received in respect of the series of preferred stock represented by the depositary shares to the record holders of depositary receipts in proportion to the number of depositary shares owned by such holders on the relevant record date, which will be the same date as the record date fixed by us for the applicable series of preferred stock. The depositary, however, will distribute only such amount as can be distributed without attributing to any depositary share a fraction of one cent, and any balance not so distributed will be added to and treated as part of the next sum received by the depositary for distribution to record holders of depositary receipts then outstanding.

In the event of a distribution other than in cash, the depositary will distribute property received by it to the record holders of depositary receipts entitled thereto, in proportion, as nearly as may be practicable, to the number of depositary shares owned by such holders on the relevant record date, unless the depositary determines (after consultation with us) that it is not feasible to make such distribution, in which case the depositary may (with our approval) adopt any other method for such distribution as it deems equitable and appropriate, including the sale of such property (at such place or places and upon such terms as it may deem equitable and appropriate) and distribution of the net proceeds from such sale to such holders.

Liquidation Preference

In the event of the liquidation, dissolution or winding up of the affairs of Ouster, whether voluntary or involuntary, the holders of each depositary share will be entitled to the fraction of the liquidation preference accorded each share of the applicable series of preferred stock as set forth in the applicable prospectus supplement.

Redemption

If the series of preferred stock represented by the applicable series of depositary shares is redeemable, such depositary shares will be redeemed from the proceeds received by the depositary resulting from the redemption, in whole or in part, of the preferred stock held by the depositary. Whenever we redeem any preferred stock held by the depositary, the depositary will redeem as of the same redemption date the number of depositary shares

representing the shares of preferred stock so redeemed. The depositary will mail the notice of redemption promptly upon receipt of such notice from us and not less than 30 nor more than 60 days prior to the date fixed for redemption of the preferred stock and the depositary shares to the record holders of the depositary receipts.

Voting

Promptly upon receipt of notice of any meeting at which the holders of the series of preferred stock represented by the applicable series of depositary shares are entitled to vote, the depositary will mail the information contained in such notice of meeting to the record holders of the depositary receipts as of the record date for such meeting. Each such record holder of depositary receipts will be entitled to instruct the depositary as to the exercise of the voting rights pertaining to the number of shares of preferred stock represented by such record holder’s depositary shares. The depositary will endeavor, insofar as practicable, to vote such preferred stock represented by such depositary shares in accordance with such instructions, and we will agree to take all action which may be deemed necessary by the depositary in order to enable the depositary to do so. The depositary will abstain from voting any of the preferred stock to the extent that it does not receive specific instructions from the holders of depositary receipts.

Withdrawal of Preferred Stock

Upon surrender of depositary receipts at the principal office of the depositary and payment of any unpaid amount due the depositary, and subject to the terms of the deposit agreement, the owner of the depositary shares evidenced thereby is entitled to delivery of the number of whole shares of preferred stock and all money and other property, if any, represented by such depositary shares. Partial shares of preferred stock will not be issued. If the depositary receipts delivered by the holder evidence a number of depositary shares in excess of the number of depositary shares representing the number of whole shares of preferred stock to be withdrawn, the depositary will deliver to such holder at the same time a new depositary receipt evidencing such excess number of depositary shares. Holders of preferred stock thus withdrawn will not thereafter be entitled to deposit such shares under the deposit agreement or to receive depositary receipts evidencing depositary shares therefor.

Amendment and Termination of Deposit Agreement

The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may at any time and from time to time be amended by agreement between us and the depositary. However, any amendment which materially and adversely alters the rights of the holders (other than any change in fees) of depositary shares will not be effective unless such amendment has been approved by at least a majority of the depositary shares then outstanding. No such amendment may impair the right, subject to the terms of the deposit agreement, of any owner of any depositary shares to surrender the depositary receipt evidencing such depositary shares with instructions to the depositary to deliver to the holder of the preferred stock and all money and other property, if any, represented thereby, except in order to comply with mandatory provisions of applicable law.

The deposit agreement will be permitted to be terminated by us upon not less than 30 days prior written notice to the applicable depositary if a majority of each series of preferred stock affected by such termination consents to such termination, whereupon such depositary will be required to deliver or make available to each holder of depositary receipts, upon surrender of the depositary receipts held by such holder, such number of whole or fractional shares of preferred stock as are represented by the depositary shares evidenced by such depositary receipts together with any other property held by such depositary with respect to such depositary receipts. In addition, the deposit agreement will automatically terminate if (a) all outstanding depositary shares thereunder shall have been redeemed, (b) there shall have been a final distribution in respect of the related preferred stock in connection with any liquidation, dissolution or winding-up of Ouster and such distribution shall have been distributed to the holders of depositary receipts evidencing the depositary shares representing such preferred stock or (c) each share of the related preferred stock shall have been converted into stock of Ouster not so represented by depositary shares.

Charges of Depositary

We will pay all transfer and other taxes and governmental charges arising solely from the existence of the depositary arrangements. We will pay charges of the depositary in connection with the initial deposit of the preferred stock and initial issuance of the depositary shares, and redemption of the preferred stock and all withdrawals of preferred stock by owners of depositary shares. Holders of depositary receipts will pay transfer, income and other taxes and governmental charges and certain other charges as are provided in the deposit agreement to be for their accounts. In certain circumstances, the depositary may refuse to transfer depositary shares, may withhold dividends and distributions and sell the depositary shares evidenced by such depositary receipt if such charges are not paid. The applicable prospectus supplement will include information with respect to fees and charges, if any, in connection with the deposit or substitution of the underlying securities, the receipt and distribution of dividends, the sale or exercise of rights, the withdrawal of the underlying security, and the transferring, splitting or grouping of receipts. The applicable prospectus supplement will also include information with respect to the right to collect the fees and charges, if any, against dividends received and deposited securities.

Miscellaneous

The depositary will forward to the holders of depositary receipts all notices, reports and proxy soliciting material from us which are delivered to the depositary and which we are required to furnish to the holders of the preferred stock. In addition, the depositary will make available for inspection by holders of depositary receipts at the principal office of the depositary, and at such other places as it may from time to time deem advisable, any notices, reports and proxy soliciting material received from us which are received by the depositary as the holder of preferred stock. The applicable prospectus supplement will include information about the rights, if any, of holders of receipts to inspect the transfer books of the depositary and the list of holders of receipts.

Neither the depositary nor Ouster assumes any obligation or will be subject to any liability under the deposit agreement to holders of depositary receipts other than for its negligence or willful misconduct. Neither the depositary nor Ouster will be liable if it is prevented or delayed by law or any circumstance beyond its control in performing its obligations under the deposit agreement. The obligations of Ouster and the depositary under the deposit agreement will be limited to performance in good faith of their duties thereunder, and they will not be obligated to prosecute or defend any legal proceeding in respect of any depositary shares or preferred stock unless satisfactory indemnity is furnished. Ouster and the depositary may rely on written advice of counsel or accountants, on information provided by holders of the depositary receipts or other persons believed in good faith to be competent to give such information and on documents believed to be genuine and to have been signed or presented by the proper party or parties.

In the event the depositary shall receive conflicting claims, requests or instructions from any holders of depositary receipts, on the one hand, and us, on the other hand, the depositary shall be entitled to act on such claims, requests or instructions received from us.

Resignation and Removal of Depositary

The depositary may resign at any time by delivering to us notice of its election to do so, and we may at any time remove the depositary, any such resignation or removal to take effect upon the appointment of a successor depositary and its acceptance of such appointment. Such successor depositary must be appointed within 60 days after delivery of the notice for resignation or removal and must be a bank or trust company having its principal office in the United States and having a combined capital and surplus of at least $150,000,000.

DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of shares of our common stock or preferred stock or of debt securities. We may issue warrants independently or together with other securities, and the warrants may be attached to or separate from any offered securities. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and the investors or a warrant agent. The following summary of material provisions of the warrants and warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to a particular series of warrants. The terms of any warrants offered under a prospectus supplement may differ from the terms described below. We urge you to read the applicable prospectus supplement and any related free writing prospectus, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants.

The particular terms of any issue of warrants will be described in the prospectus supplement relating to the issue. Those terms may include:

Holders of equity warrants will not be entitled:

Each warrant will entitle its holder to purchase the principal amount of debt securities or the number of shares of preferred stock or common stock at the exercise price set forth in, or calculable as set forth in, the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

A holder of warrant certificates may exchange them for new warrant certificates of different denominations, present them for registration of transfer and exercise them at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement. Until any warrants to purchase debt securities are exercised, the holder of the warrants will not have any rights of holders of the debt securities that can be purchased upon exercise, including any rights to receive payments of principal, premium or interest on the underlying debt securities or to enforce covenants in the applicable indenture. Until any warrants to purchase common stock or preferred stock are exercised, the holders of the warrants will not have any rights of holders of the underlying common stock or preferred stock, including any rights to receive dividends or payments upon any liquidation, dissolution or winding up on the common stock or preferred stock, if any.

DESCRIPTION OF PURCHASE CONTRACTS

We may issue purchase contracts for the purchase or sale of debt or equity securities issued by us. Each purchase contract will entitle the holder thereof to purchase or sell, and obligate us to sell or purchase, on specified dates, such securities at a specified purchase price, which may be based on a formula, all as set forth in the applicable prospectus supplement. Any purchase contracts we issue will be physically settled by delivery of such securities. The applicable prospectus supplement will also specify the methods by which the holders may purchase or sell such securities and any acceleration, cancellation or termination provisions or other provisions relating to the settlement of a purchase contract.

DESCRIPTION OF UNITS

We may issue units consisting of any combination of the other types of securities offered under this prospectus in one or more series. We may evidence each series of units by unit certificates that we will issue under a separate agreement. We may enter into unit agreements with a unit agent. Each unit agent will be a bank or trust company that we select. We will indicate the name and address of the unit agent in the applicable prospectus supplement relating to a particular series of units. The terms of any units offered under a prospectus supplement may differ from the terms described below. We urge you to read the applicable prospectus supplement and any related free writing prospectus, as well as the complete unit certificate that contains the terms of the units.

The following description, together with the additional information included in any applicable prospectus supplement, summarizes the general features of the units that we may offer under this prospectus. You should read any prospectus supplement and any free writing prospectus that we may authorize to be provided to you related to the series of units being offered, as well as the complete unit agreements that contain the terms of the units. Specific unit agreements will contain additional important terms and provisions and we will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from another report that we file with the SEC, the form of each unit agreement relating to units offered under this prospectus.

If we offer any units, certain terms of that series of units will be described in the applicable prospectus supplement, including, without limitation, the following, as applicable:

GLOBAL SECURITIES

Book-Entry, Delivery and Form

Unless we indicate differently in any applicable prospectus supplement or free writing prospectus, the securities initially will be issued in book-entry form and represented by one or more global notes or global securities, or, collectively, global securities. The global securities will be deposited with, or on behalf of, The Depository Trust Company, New York, New York, as depositary, or DTC, and registered in the name of Cede & Co., the nominee of DTC. Unless and until it is exchanged for individual certificates evidencing securities under the limited circumstances described below, a global security may not be transferred except as a whole by the depositary to its nominee or by the nominee to the depositary, or by the depositary or its nominee to a successor depositary or to a nominee of the successor depositary.

DTC has advised us that it is:

DTC holds securities that its participants deposit with DTC. DTC also facilitates the settlement among its participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerized book-entry changes in participants’ accounts, thereby eliminating the need for physical movement of securities certificates. “Direct participants” in DTC include securities brokers and dealers, including underwriters, banks, trust companies, clearing corporations and other organizations. DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation, or DTCC. DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others, which we sometimes refer to as indirect participants, that clear through or maintain a custodial relationship with a direct participant, either directly or indirectly. The rules applicable to DTC and its participants are on file with the SEC.

Purchases of securities under the DTC system must be made by or through direct participants, which will receive a credit for the securities on DTC’s records. The ownership interest of the actual purchaser of a security, which we sometimes refer to as a beneficial owner, is in turn recorded on the direct and indirect participants’ records. Beneficial owners of securities will not receive written confirmation from DTC of their purchases. However, beneficial owners are expected to receive written confirmations providing details of their transactions, as well as periodic statements of their holdings, from the direct or indirect participants through which they purchased securities. Transfers of ownership interests in global securities are to be accomplished by entries made on the books of participants acting on behalf of beneficial owners. Beneficial owners will not receive certificates representing their ownership interests in the global securities, except under the limited circumstances described below.

To facilitate subsequent transfers, all global securities deposited by direct participants with DTC will be registered in the name of DTC’s partnership nominee, Cede & Co., or such other name as may be requested by an authorized representative of DTC. The deposit of securities with DTC and their registration in the name of Cede & Co. or such other nominee will not change the beneficial ownership of the securities. DTC has no knowledge of the actual beneficial owners of the securities. DTC’s records reflect only the identity of the direct participants to whose accounts the securities are credited, which may or may not be the beneficial owners. The participants are responsible for keeping account of their holdings on behalf of their customers.

So long as the securities are in book-entry form, you will receive payments and may transfer securities only through the facilities of the depositary and its direct and indirect participants. If applicable, we will maintain an office or agency in the location specified in the prospectus supplement for the applicable securities, where notices and demands in respect of the securities and the indenture may be delivered to us and where certificated securities may be surrendered for payment, registration of transfer or exchange.

Conveyance of notices and other communications by DTC to direct participants, by direct participants to indirect participants and by direct participants and indirect participants to beneficial owners will be governed by arrangements among them, subject to any legal requirements in effect from time to time.

Redemption notices will be sent to DTC. If less than all of the securities of a particular series are being redeemed, DTC’s practice is to determine by lot the amount of the interest of each direct participant in the securities of such series to be redeemed.

Neither DTC nor Cede & Co. (or such other DTC nominee) will consent or vote with respect to the securities. Under its usual procedures, DTC will provide us with an omnibus proxy as soon as possible after the record date. The omnibus proxy assigns the consenting or voting rights of Cede & Co. to those direct participants to whose accounts the securities of such series are credited on the record date, identified in a listing attached to the omnibus proxy.

So long as securities are in book-entry form, we will make payments on those securities to the depositary or its nominee, as the registered owner of such securities, by wire transfer of immediately available funds. If securities are issued in definitive certificated form under the limited circumstances described below and unless if otherwise provided in the description of the applicable securities herein or in the applicable prospectus supplement, we will have the option of making payments by check mailed to the addresses of the persons entitled to payment or by wire transfer to bank accounts in the United States designated in writing to the applicable trustee or other designated party at least 15 days before the applicable payment date by the persons entitled to payment, unless a shorter period is satisfactory to the applicable trustee or other designated party.

Redemption proceeds, distributions and dividend payments on the securities will be made to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC. DTC’s practice is to credit direct participants’ accounts upon DTC’s receipt of funds and corresponding detail information from us on the payment date in accordance with their respective holdings shown on DTC records. Payments by participants to beneficial owners will be governed by standing instructions and customary practices, as is the case with securities held for the account of customers in bearer form or registered in “street name.” Those payments will be the responsibility of participants and not of DTC or us, subject to any statutory or regulatory requirements in effect from time to time. Payment of redemption proceeds, distributions and dividend payments to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC, is our responsibility, disbursement of payments to direct participants is the responsibility of DTC, and disbursement of payments to the beneficial owners is the responsibility of direct and indirect participants.

Except under the limited circumstances described below, purchasers of securities will not be entitled to have securities registered in their names and will not receive physical delivery of securities. Accordingly, each beneficial owner must rely on the procedures of DTC and its participants to exercise any rights under the securities and the indenture.

The laws of some jurisdictions may require that some purchasers of securities take physical delivery of securities in definitive form. Those laws may impair the ability to transfer or pledge beneficial interests in securities.

DTC may discontinue providing its services as securities depositary with respect to the securities at any time by giving reasonable notice to us. Under such circumstances, in the event that a successor depositary is not obtained, securities certificates are required to be printed and delivered.

As noted above, beneficial owners of a particular series of securities generally will not receive certificates representing their ownership interests in those securities. However, if:

we will prepare and deliver certificates for such securities in exchange for beneficial interests in the global securities. Any beneficial interest in a global security that is exchangeable under the circumstances described in the preceding sentence will be exchangeable for securities in definitive certificated form registered in the names that the depositary directs. It is expected that these directions will be based upon directions received by the depositary from its participants with respect to ownership of beneficial interests in the global securities.

Euroclear and Clearstream

If so provided in the applicable prospectus supplement, you may hold interests in a global security through Clearstream Banking S.A., which we refer to as “Clearstream,” or Euroclear Bank S.A./N.V., as operator of the Euroclear System, which we refer to as “Euroclear,” either directly if you are a participant in Clearstream or Euroclear or indirectly through organizations which are participants in Clearstream or Euroclear. Clearstream and Euroclear will hold interests on behalf of their respective participants through customers’ securities accounts in the names of Clearstream and Euroclear, respectively, on the books of their respective U.S. depositaries, which in turn will hold such interests in customers’ securities accounts in such depositaries’ names on DTC’s books.

Clearstream and Euroclear are securities clearance systems in Europe. Clearstream and Euroclear hold securities for their respective participating organizations and facilitate the clearance and settlement of securities transactions between those participants through electronic book-entry changes in their accounts, thereby eliminating the need for physical movement of certificates.

Payments, deliveries, transfers, exchanges, notices and other matters relating to beneficial interests in global securities owned through Euroclear or Clearstream must comply with the rules and procedures of those systems. Transactions between participants in Euroclear or Clearstream, on one hand, and other participants in DTC, on the other hand, are also subject to DTC’s rules and procedures.

Investors will be able to make and receive through Euroclear and Clearstream payments, deliveries, transfers and other transactions involving any beneficial interests in global securities held through those systems only on days when those systems are open for business. Those systems may not be open for business on days when banks, brokers and other institutions are open for business in the United States.

Cross-market transfers between participants in DTC, on the one hand, and participants in Euroclear or Clearstream, on the other hand, will be effected through DTC in accordance with the DTC’s rules on behalf of Euroclear or Clearstream, as the case may be, by their respective U.S. depositaries; however, such cross-market transactions will require delivery of instructions to Euroclear or Clearstream, as the case may be, by the counterparty in such system in accordance with the rules and procedures and within the established deadlines (European time) of such system. Euroclear or Clearstream, as the case may be, will, if the transaction meets its settlement requirements, deliver instructions to its U.S. depositary to take action to effect final settlement on its behalf by delivering or receiving interests in the global securities through DTC, and making or receiving payment in accordance with normal procedures for same-day fund settlement. Participants in Euroclear or Clearstream may not deliver instructions directly to their respective U.S. depositaries.

Due to time zone differences, the securities accounts of a participant in Euroclear or Clearstream purchasing an interest in a global security from a direct participant in DTC will be credited, and any such crediting will be reported to the relevant participant in Euroclear or Clearstream, during the securities settlement processing day (which must be a business day for Euroclear or Clearstream) immediately following the settlement date of DTC. Cash received in Euroclear or Clearstream as a result of sales of interests in a global security by or through a participant in Euroclear or Clearstream to a direct participant in DTC will be received with value on the settlement date of DTC but will be available in the relevant Euroclear or Clearstream cash account only as of the business day for Euroclear or Clearstream following DTC’s settlement date.

Other

The information in this section of this prospectus concerning DTC, Clearstream, Euroclear and their respective book-entry systems has been obtained from sources that we believe to be reliable, but we do not take responsibility for this information. This information has been provided solely as a matter of convenience. The rules and procedures of DTC, Clearstream and Euroclear are solely within the control of those organizations and could change at any time. Neither we nor the trustee nor any agent of ours or of the trustee has any control over those entities and none of us takes any responsibility for their activities. You are urged to contact DTC, Clearstream and Euroclear or their respective participants directly to discuss those matters. In addition, although we expect that DTC, Clearstream and Euroclear will perform the foregoing procedures, none of them is under any obligation to perform or continue to perform such procedures and such procedures may be discontinued at any time. Neither we nor any agent of ours will have any responsibility for the performance or nonperformance by DTC, Clearstream and Euroclear or their respective participants of these or any other rules or procedures governing their respective operations.

PLAN OF DISTRIBUTION

We may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions or block trades or through underwriters or dealers, through agents and/or directly to one or more purchasers, or a combination of these methods. The securities may be distributed from time to time in one or more transactions:

Each time that we sell securities covered by this prospectus, we will provide a prospectus supplement or supplements that will describe the method of distribution and set forth the terms and conditions of the offering of such securities, including the offering price of the securities and the proceeds to us, to the extent appropriate.

Offers to purchase the securities being offered by this prospectus may be solicited directly. Agents may also be designated to solicit offers to purchase the securities from time to time. Any agent involved in the offer or sale of our securities will be identified in a prospectus supplement, to the extent appropriate.

If a dealer is utilized in the sale of the securities being offered by this prospectus, the securities will be sold to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale.

If an underwriter is utilized in the sale of the securities being offered by this prospectus, an underwriting agreement will be executed with the underwriter at the time of sale and the name of any underwriter will be provided in the prospectus supplement that the underwriter will use to make resales of the securities to the public. In connection with the sale of the securities, we or the purchasers of securities for whom the underwriter may act as agent, may compensate the underwriter in the form of underwriting discounts or commissions. The underwriter may sell the securities to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for which they may act as agent. Unless otherwise indicated in a prospectus supplement, an agent will be acting on a best efforts basis and a dealer will purchase securities as a principal, and may then resell the securities at varying prices to be determined by the dealer.

Any compensation paid to underwriters, dealers or agents in connection with the offering of the securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers will be provided in the applicable prospectus supplement, to the extent appropriate. Underwriters, dealers and agents participating in the distribution of the securities may be deemed to be underwriters within the meaning of the Securities Act of 1933, as amended, and any discounts and commissions received by them and any profit realized by them on resale of the securities may be deemed to be underwriting discounts and commissions. We may enter into agreements to indemnify underwriters, dealers and agents against civil liabilities, including liabilities under the Securities Act, or to contribute to payments they may be required to make in respect thereof and to reimburse those persons for certain expenses.

Any common stock will be listed on the New York Stock Exchange, but any other securities may or may not be listed on a national securities exchange. To facilitate the offering of securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. This may include over-allotments or short sales of the securities, which involve the sale by persons participating in the offering of more securities than were sold to them. In these circumstances, these persons would cover such over-allotments or short positions by making purchases in the open market or by exercising their over-allotment

option, if any. In addition, these persons may stabilize or maintain the price of the securities by bidding for or purchasing securities in the open market or by imposing penalty bids, whereby selling concessions allowed to dealers participating in the offering may be reclaimed if securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. These transactions may be discontinued at any time.

We may engage in at the market offerings into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act. In addition, we may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement so indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third party may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock. The third party in such sale transactions will be an underwriter and, if not identified in this prospectus, will be named in the applicable prospectus supplement (or a post-effective amendment). In addition, we may otherwise loan or pledge securities to a financial institution or other third party that in turn may sell the securities short using this prospectus and an applicable prospectus supplement. Such financial institution or other third party may transfer its economic short position to investors in our securities or in connection with a concurrent offering of other securities.

The material terms of any lock-up provisions in respect of any given offering will be described in the applicable prospectus supplement.

The underwriters, dealers and agents may engage in transactions with us, or perform services for us, in the ordinary course of business for which they receive compensation.

LEGAL MATTERS

Latham & Watkins LLP will pass upon certain legal matters relating to the issuance and sale of the securities offered hereby on behalf of Ouster, Inc. Additional legal matters may be passed upon for us or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.

EXPERTS

The financial statements incorporated in this Prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2021 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

The information in this prospectus supplement is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus supplement is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, dated April 29, 2022

PROSPECTUS SUPPLEMENT

(To prospectus dated             , 2022)

Ouster, Inc.

Up to $150,000,000

Common Stock

We have entered into an At Market Issuance Sales Agreement (the “Sales Agreement”) with B. Riley Securities, Inc., Cantor Fitzgerald & Co. and Oppenheimer & Co. Inc. (each, an “Agent” and, collectively, the “Agents”) relating to shares of our common stock, $0.0001 par value per share (“Common Stock”), offered by this prospectus supplement and the accompanying prospectus. In accordance with the terms of the Sales Agreement, from time to time we may offer and sell shares of our Common Stock having an aggregate gross sales price of up to $150,000,000 through or to the applicable Agent, acting as sales agent or principal, pursuant to this prospectus supplement and the accompanying prospectus.

Sales of our Common Stock, if any, under this prospectus supplement may be made in sales deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the “Securities Act”). Subject to terms of the Sales Agreement, the Agents are not required to sell any specific number or dollar amounts of our Common Stock but will use commercially reasonable efforts consistent with its normal trading and sales practices, on mutually agreed terms between the Agents and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The Agents will be entitled to compensation under the terms of the Sales Agreement at a commission rate of 3.0% of the gross proceeds from each sale of our Common Stock. In connection with the sales of our Common Stock on our behalf, each of the Agents will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of the Agents will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contributions to the Agents against certain liabilities, including liabilities under the Securities Act and the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

Our Common Stock is listed on the New York Stock Exchange (the “NYSE”) under the symbol “OUST”. On April 28, 2022, the last reported sale price of our common stock was $3.40 per share.

Investing in our Common Stock involves significant risks. See “Risk Factors” beginning on page S-3 of this prospectus supplement and the risk factors that are incorporated by reference into this prospectus supplement and the accompanying prospectus from our filings made with the Securities and Exchange Commission (the “SEC”) pursuant to the Exchange Act for a discussion of the factors you should carefully consider before deciding to invest in our Common Stock.

Neither the SEC nor any state securities commission has approved or disapproved of our Common Stock or determined if this prospectus supplement or the accompanying prospectus is accurate, truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is                     , 2022.

TABLE OF CONTENTS

Prospectus Supplement

Prospectus

S-i

ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement relates to the offering of shares of our common stock having an aggregate offering price of up to $150,000,000 from time to time pursuant to an At Market Issuance Sales Agreement (the “Sales Agreement”) with B. Riley Securities, Inc. (“B. Riley Securities”), Cantor Fitzgerald & Co. (“Cantor”) and Oppenheimer & Co. Inc. (collectively with B. Riley Securities and Cantor, the “Agents”). Before buying any of the shares of common stock that we are offering, we urge you to carefully read this prospectus supplement, together with the information incorporated by reference as described under the headings “Where You Can Find Additional Information; Incorporation by Reference” in this prospectus supplement, the accompanying prospectus and any free writing prospectus that we have authorized for use in connection with this offering. These documents contain important information that you should consider when making your investment decision. In general, when we refer to the prospectus, we are referring to both the prospectus supplement and the accompanying prospectus combined.

This prospectus describes the terms of this offering of shares of common stock and also adds to and updates information contained in the documents incorporated by reference into this prospectus. To the extent there is a conflict between the information contained in this prospectus, on the one hand, and the information contained in any document incorporated by reference into this prospectus that was filed with the Securities and Exchange Commission (the “SEC”) before the date of this prospectus, on the other hand, you should rely on the information in this prospectus. 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 into this prospectus—the statement in the document having the later date modifies or supersedes the earlier statement.

We have not, and the Agents have not, authorized any other person to provide you with information that is in addition to or different from that contained or incorporated by reference in this prospectus, along with the information contained in any permitted free writing prospectuses we have authorized for use in connection with this offering. Neither we nor the Agents take any responsibility for, or can provide any assurance as to the reliability of, any information other than the information contained or incorporated by reference in this prospectus or any permitted free writing prospectuses we have authorized for use in connection with this offering. You should assume that the information appearing in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference into this prospectus, and in any free writing prospectus that we may authorize for use in connection with this offering, is accurate only as of the date of those respective documents or any earlier date specified for such information unless we indicate otherwise. Our business, financial condition, results of operations and prospects may have changed since those dates. You should read this prospectus supplement, the accompanying prospectus, the documents incorporated by reference into this prospectus, and any free writing prospectus that we may authorize for use in connection with this offering, in their entirety before making an investment decision.

Information contained on, or accessible through, our website is not part of this prospectus. We and the Agents are offering to sell, and seeking offers to buy, shares of common stock only in jurisdictions where offers and sales are permitted. The distribution of this prospectus and the offering of the common stock 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 the common stock and the distribution of this prospectus outside the United States. This prospectus does 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.

Unless the context otherwise requires, we use the terms “Ouster,” “company,” “we,” “us,” and “our” in this prospectus to refer to Ouster, Inc. and its subsidiaries.

S-ii

PROSPECTUS SUPPLEMENT SUMMARY

The following summary highlights information contained elsewhere in this prospectus supplement and the accompanying prospectus and documents incorporated by reference. It does not contain all of the information that may be important to you. You should read this entire prospectus supplement and the accompanying prospectus and documents incorporated by reference carefully, including the section titled “Risk Factors” and our historical consolidated financial statements and related notes incorporated by reference herein.

Ouster is building the eyes of autonomy. We are a leading provider of high-resolution digital lidar sensors and enabling software that gives robots, machinery, vehicles and fixed infrastructure advanced 3D vision allowing them to safely interact with the physical world.

We design and manufacture digital lidar sensors that we believe to be the highest performing, lowest cost lidar solutions available today across each of our four target markets: automotive, industrial automation; smart infrastructure and robotics. We believe that our digital lidar technology positions us at the center of a global revolution in autonomy. We believe that 3D vision technologies, coupled with artificial intelligence, will power new autonomous technologies that in turn will fundamentally disrupt business models across many existing industries and also enable entirely new industries and capabilities.

Beyond the automotive market, we believe that there is an even larger market for lidar sensors. We believe our highly flexible digital lidar architecture strongly positions us to address what we believe is a rapidly growing demand. Our industrial customers today are using lidar to increase safety and automating operations across the global supply chain, in material handling vehicles at ports and warehouses, in off-highway vehicles at mines and farms, and in manufacturing equipment in factories. In our smart infrastructure vertical, cities are increasing safety and efficiency through using lidar control traffic lights and warning systems, and security companies are improving intrusion detection and tracking by augmenting existing CCTV systems with the spatial tracking capabilities of lidar. We believe these markets present a significant opportunity for growth, as they touch nearly every aspect of our daily lives.

We envision a future where lidar-powered solutions are widespread, with useful and affordable 3D perception capabilities built into every moving robot, car, truck and drone, as well as every factory, building, stoplight, dock, and airport terminal.

The registrant was initially incorporated under the name “Colonnade Acquisition Corp.” on June 4, 2020 as a Cayman Islands exempted company for purposes of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses. On March 10, 2021, the registrant domesticated into a Delaware corporation and changed our name to “Ouster, Inc.” in connection with the consummation of the business combination with Ouster Technologies, Inc. Following the business combination, the operations of Ouster Technologies, Inc. were the only ongoing operations of the registrant.

Our principal executive office is located at 350 Treat Avenue, San Francisco, CA 94110. Our telephone number is (415) 949-0108. Our website address is www.ouster.com. Information contained on our website is not a part of this prospectus, and the inclusion of our website address in this prospectus is an inactive textual reference only.

THE OFFERING

The number of shares of our common stock that will be outstanding immediately after this offering as shown above is based on 172,200,417 shares of common stock issued and outstanding as of December 31, 2021 and excludes:

Unless otherwise indicated, all information in this prospectus supplement assumes no exercise of the outstanding warrants or options or settlement of the outstanding RSUs referred to above.

RISK FACTORS

Investing in our securities involves risks. You should carefully consider the risks, uncertainties and other factors described in our most recent Annual Report on Form 10-K, as supplemented and updated by subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K that we have filed or will file with the SEC, and in other documents which are incorporated by reference into this prospectus supplement, including the risk factors and other information contained in or incorporated by reference into this prospectus supplement before investing in any of our securities. Our business, financial condition, results of operations, cash flows or prospects could be materially adversely affected by any of these risks. The risks and uncertainties described in the documents incorporated by reference herein are not the only risks and uncertainties that we may face.

Risks Relating to Our Common Stock and this Offering

We have broad discretion as to the use of proceeds from this offering and may not use the proceeds effectively.

Our management will retain broad discretion as to the allocation of the proceeds and may spend these proceeds in ways in which you may not agree. The failure of our management to apply these funds effectively could result in unfavorable returns and uncertainty about our prospects, each of which could cause the price of our common stock to decline.

If you purchase shares of our common stock in this offering, you will incur immediate and substantial dilution.

The price per share of common stock being offered may be higher than the net tangible book value per share of our outstanding common stock. Assuming that an aggregate of 44,117,647 shares of common stock are sold at a price of $3.40 per share, the last reported sale price of shares of our common stock on the NYSE on April 28, 2022, for aggregate gross proceeds of $150,000,000, and after deducting commissions and estimated offering expenses payable by us, new investors in this offering would incur immediate dilution of $1.87 per share. In addition, you may also experience additional dilution after this offering on any future equity issuances, including the issuance of any shares under an employee stock purchase plan that we intend to present to our stockholders for approval at our 2022 annual meeting of stockholders. To the extent we issue equity securities, our stockholders will experience substantial additional dilution. See “Dilution” for additional information.

The actual number of shares of common stock 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 a placement notice to the Agents at any time throughout the term of the Sales Agreement. The number of shares of common stock that are sold by an Agent after our delivery of a placement notice to such Agent will depend on the market price of the shares of common stock during the sales period and limits we set with the Agents. Because the price per share of each share sold will fluctuate based on the market price of shares of our common stock during the sales period, it is not possible at this stage to predict the number of shares of common stock that will or may be ultimately issued.

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

Investors who purchase shares of common stock in this offering at different times will likely pay different prices, and so may experience different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices, and numbers of shares of common stock sold, and there is no minimum or maximum per share sales price. Investors may experience a decline in the value of their shares of common stock as a result of share sales made at prices lower than the prices they paid.

USE OF PROCEEDS

We will retain broad discretion over the use of the net proceeds, if any, from the sale of the securities offered hereby. We may issue and sell shares of common stock having aggregate sales proceeds of up to $150,000,000 from time to time. Because there is no minimum offering amount required as a condition to close this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time.

We intend to use the net proceeds from the sale by us of the securities to which this prospectus supplement relates for general corporate purposes, including working capital. We may also use a portion of our net proceeds to co-develop, acquire or invest in products, technologies or businesses that are complementary to our business. However, we currently have no agreements or commitments to complete any such transaction.

Pending the use of the net proceeds, we may invest the proceeds in interest-bearing, investment-grade securities, certificates of deposit or government securities.

DILUTION

If you invest in our common stock in this offering, your ownership interest will be immediately diluted to the extent of the difference between the assumed public offering price per share and the as adjusted net tangible book value per share of our common stock after this offering.

Historical net tangible book value per share represents our total tangible assets less our total liabilities divided by the total number of shares of common stock outstanding. As of December 31, 2021, our historical net tangible book value was approximately $186.9 million, or $1.09 per share, based on 172,200,417 shares of common stock outstanding as of that date.

After giving effect to receipt of the net proceeds from our sale of shares of our common stock at an assumed public offering price of $3.40 per share, the last reported sale price of our common stock on the NYSE on April 28, 2022, after deducting the estimated commissions and estimated offering expenses payable by us, our as adjusted net tangible book value as of December 31, 2021 would have been approximately $332.0 million, or $1.53 per share. This represents an immediate increase in as adjusted net tangible book value of $0.44 per share to our existing stockholders and an immediate dilution of $1.87 per share to new investors participating in this offering.

The following table illustrates this dilution to new investors on a per share basis:

The shares sold in this offering, if any, will be sold from time to time at various prices. An increase of $1.00 per share in the price at which the shares are sold from an assumed offering price of $3.40 per share shown in the table above, assuming all of our common stock in the aggregate amount of $150,000,000 is sold at that price, would cause our as adjusted net tangible book value per share after the offering to be $1.61 per share and would increase the dilution in net tangible book value per share to new investors to $2.79 per share, after deducting commissions and estimated aggregate offering expenses payable by us. A decrease of $1.00 per share in the price at which the shares are sold from an assumed offering price of $3.40 per share shown in the table above, assuming all of our common stock in the aggregate amount of $150,000,000 is sold at that price, would cause our as adjusted net tangible book value per share after the offering to be $1.41 per share and would decrease the dilution in net tangible book value per share to new investors to $0.99 per share, after deducting commissions and estimated aggregate offering expenses payable by us. This information is supplied for illustrative purposes only.

To the extent that outstanding options are exercised or outstanding restricted stock awards vest, investors purchasing our common stock in this offering will experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. Further, to the extent that we raise additional capital through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

The number of shares of our common stock that will be outstanding immediately after this offering as shown above is based on 172,200,417 shares of common stock issued and outstanding as of December 31, 2021 and excludes:

Unless otherwise indicated, all information in this prospectus supplement assumes no exercise of the outstanding warrants or options or settlement of the outstanding RSUs referred to above.

PLAN OF DISTRIBUTION

We have entered into the Sales Agreement with B. Riley Securities, Inc., Cantor Fitzgerald & Co. and Oppenheimer & Co. Inc., pursuant to which we may issue and sell shares of our common stock having an aggregate gross sales price of up to $150,000,000 from time to time through or to the applicable Agent, acting as sales agent or principal. The Sales Agreement has been filed as an exhibit to the registration statement of which this prospectus supplement and accompanying prospectus form a part.

Following delivery of a placement notice and subject to the terms and conditions of the Sales Agreement, the Agents may offer and sell our common stock 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. We may instruct the Agents not to sell our common stock if the sales cannot be effected at or above the price designated by us from time to time. We or the Agents may suspend the offering of our Common Stock upon notice and subject to other conditions.

We will pay the Agents’ commission, in cash, for their services in acting as agents in the sale of our common stock. The Agents will be entitled to compensation under the terms of the Sales Agreement at a commission rate of 3.0% of the gross proceeds from each sale of our common stock made by such Agent. Because there is no minimum offering amount required pursuant to the Sales Agreement, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. We have also agreed to reimburse each of the Agents for certain specified fees and documented expenses, including the reasonable and documented out-of-pocket fees and disbursements of counsel to the Agents not to exceed $75,000 in connection with the filing of the Sales Agreement with the SEC and (y) not to exceed $5,000 per calendar quarter thereafter in connection with any updates at the time of certain filings as described in the Sales Agreement. We estimate that the total expenses for this offering, excluding compensation and reimbursements payable to the Agents under the terms of the Sales Agreement, will be approximately $0.5 million.

Settlement for sales of our common stock will occur on the second trading day following the date on which any sales are made, or on some other date that is agreed upon by us and the applicable Agent 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 supplement will be settled through the facilities of The Depository Trust Company or by such other means as we and the applicable Agent may agree upon. There is no arrangement for funds to be received in an escrow, trust or similar arrangement. The Agents will use commercially reasonable efforts consistent with their normal trading and sales practices to solicit offers to purchase the shares of our common stock under the terms and subject to the conditions set forth in the Sales Agreement. In connection with the sales of our common stock on our behalf, each of the Agents will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of the Agents will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contributions to the Agents against certain liabilities, including liabilities under the Securities Act and the Exchange Act.

This offering of our common stock pursuant to the Sales Agreement will terminate as permitted therein. We, on the one hand, and each of the Agents, on the other hand, may terminate the Sales Agreement at any time upon five days’ prior notice.

Each of the Agents and its affiliates may in the future provide various investment banking, commercial banking and other financial services for us and our affiliates, for which services it may in the future receive customary fees and compensation. To the extent required by Regulation M, the Agents will engage in any market making activities involving our common stock while the offering is ongoing under this prospectus supplement.

This prospectus supplement in electronic format may be made available on a website maintained by the applicable Agent, and the applicable Agent may distribute this prospectus supplement electronically.

LEGAL MATTERS

The validity of the shares of common stock offered hereby will be passed upon for us by Latham & Watkins LLP. The Agents are being represented in connection with this offering by Duane Morris LLP.

EXPERTS

The financial statements incorporated in this Prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2021 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE

Available Information

We have filed with the SEC a registration statement on Form S-3 under(File No. 333-271845) (as amended, the Securities Act with respect“Registration Statement”) as an exhibit-only filing. Accordingly, this Amendment consists only of the facing page, this explanatory note, Part II of the Registration Statement, the signature page to among other securities, the shares of common stock offered by this prospectus supplement and accompanying prospectus. This prospectus supplementRegistration Statement and the accompanying prospectus do not contain allfiled exhibits. The remainder of the information included in the registration statement. For further information pertaining to usRegistration Statement is unchanged and our common stock we are offering under this prospectus supplement and the accompanying prospectus, you should refer to the registration statement and its exhibits. Statements contained in this prospectus supplement and the accompanying prospectus concerning any of our contracts, agreements or other documents are not necessarily complete. If a contract or document has therefore been filed as an exhibit to the registration statement, we refer you to the copy of the contract or document that has been filed. Each statement in this prospectus supplement and the accompanying prospectus relating to a contract or document filed as an exhibit is qualified in all respects by the filed exhibit.

We are subject to the informational requirements of the Exchange Act and file annual, quarterly and current reports and other information with the SEC. Our filings with the SEC are available to the public on the SEC’s website at http://www.sec.gov. You may access these materials free of charge as soon as reasonably practicable after they are electronically filed with or furnished to the SEC. Those filings are also available to the public on, or accessible through, our website at investors.ouster.com. The information on our web site, however, is not, and should not be deemed to be, a part of this prospectus supplement and accompanying prospectus.

Incorporation by Reference

The SEC’s rules allow us to “incorporate by reference” information into this prospectus supplement and accompanying prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus supplement and accompanying prospectus, and subsequent information that we file with the SEC will automatically update and supersede that information. Any statement contained in this prospectus supplement and accompanying prospectus or a previously filed document incorporated by reference will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus supplement and accompanying prospectus or a subsequently filed document incorporated by reference modifies or replaces that statement.

This prospectus supplement and the accompanying prospectus incorporate by reference the documents set forth below that have previously been filed with the SEC:

All reports and other documents we subsequently file pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, prior to the termination of this offering, including all such documents we may file with the SEC after the date of the initial registration statement and prior to the effectiveness of the registration statement, but excluding any information furnished to, rather than filed with, the SEC, will also be incorporated by reference into this prospectus supplement and deemed to be part of this prospectus supplement from the date of the filing of such reports and documents.

You may request a free copy of any of the documents incorporated by reference in this prospectus supplement by writing or telephoning us at the following address:

Ouster, Inc.

350 Treat Avenue

San Francisco, California 94110

(415) 949-0108

Exhibits to the filings will not be sent, however, unless those exhibits have specifically been incorporated by reference in this prospectus or any accompanying prospectus supplement.

Up to $150,000,000

Common Stock

PROSPECTUS SUPPLEMENT

                    , 2022

omitted.

Section 145, or in defense of any claim, issue or matter therein, such person shall be indemnified against expenses (including attorneys’ fees) actually and reasonably incurred by such person in connection therewith; that indemnification provided for by Section 145 shall not be deemed exclusive of any other rights to which the indemnified party may be entitled; and the indemnification provided for by Section 145 shall, unless otherwise provided when authorized or ratified, continue as to a person who has ceased to be a director, officer, employee or agent and shall inure to the benefit of such person’s heirs, executors and administrators. Section 145 also empowers the corporation to purchase and maintain insurance on behalf of any person who is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise against any liability asserted against such person and incurred by such person in any such capacity, or arising out of his status as such, whether or not the corporation would have the power to indemnify such person against such liabilities under Section 145.

II-1

II-2

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communications that is an offer in the offering made by the undersigned registrant to the purchaser.

(b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(h) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

II-5