CBRE Acquisition Holdings, Inc., a Delaware corporation, which we refer to as “CBAH,” “we,” “us,” or “our,” is a blank check company incorporated as a Delaware corporation on October 13, 2020 and formed solely for the purpose of effecting a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or similar business combination with one or more businesses.

On December 15, 2020, CBAH consummated its initial public offering of 40,250,000 SAIL^SM securities, including the issuance of 5,250,000 SAIL^SM securities as a result of the underwriter’s exercise of its over-allotment option, with each SAIL^SM security consisting of one share of CBAH Class A common stock and one-fourth (1/4) of one Redeemable Warrant, each whole Redeemable Warrant entitling the holder thereof to purchase one share of CBAH Class A common stock for $11.00 per share. The SAIL^SM securities were sold at an offering price of $10.00 per unit, generating gross proceeds of $402,500,000. Simultaneously with the consummation of the CBAH IPO, CBAH consummated the private placement of 7,366,667 Private Placement Warrants at a price of $1.50 per warrant, generating total proceeds of $11,050,000. Transaction costs amounted to approximately $22,926,943 (including the deferred underwriting discount of $14,087,500 held in the trust account, which amount will be payable upon the consummation of our business combination, if consummated). In addition, $1,500,000 of cash was held outside of the trust account upon closing of the CBAH IPO and was available for working capital purposes and for the payment of offering expenses.

Following the consummation of the CBAH IPO, $402,500,000 was deposited into a U.S.-based trust account with Continental Stock Transfer & Trust Company acting as trustee. Except as described in the prospectus for the CBAH IPO, these proceeds will not be released until the earlier of the completion of an initial business combination and CBAH’s redemption of 100% of the outstanding public shares upon its failure to consummate a business combination within the completion window.

Altus, a Delaware corporation headquartered in Stamford, Connecticut, is a developer, owner and operator of large-scale roof, ground and carport-based photovoltaic and energy storage systems, as well as electric vehicle charging facilities, serving commercial and industrial, public sector and community solar customers. See the sections entitled “Information About Altus,” “Altus’s Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Management after the Business Combination.”

On July 12, 2021, CBAH entered into the Business Combination Agreement with First Merger Sub, Second Merger Sub, Holdings, APAM and Altus, providing for, among other things, and subject to the terms and conditions therein, a business combination between Altus and CBAH.

Subject to the terms of the Business Combination Agreement, at the reference price of $10.00 per share of CBAH Class A common stock, the total Merger Consideration of 90,000,000 shares of CBAH Class A common stock would have a value of $900,000,000. Merger Consideration issued to holders of Altus Common Stock does not represent consideration from an accounting perspective. For more information regarding how the Merger will be accounted for, please see the section entitled “The Business Combination - Expected Accounting Treatment” and “Description of the Merger” within the section entitled “Unaudited Pro Forma Condensed Combined Financial Information.”

In connection with the Business Combination Agreement: (a) CBAH, the Sponsor and certain officers of CBAH entered into the Sponsor Support Agreement, pursuant to which, among other things, each Sponsor Party has agreed to, among other things, vote in favor of the business combination proposal

and the other proposals included in the accompanying proxy statement/prospectus and to not redeem or transfer any shares of CBAH common stock or warrants to purchase shares of CBAH common stock, subject to certain exceptions set forth therein and (b) certain Altus stockholders entered into the Altus Stockholders Support Agreement, pursuant to which, each such Altus stockholder has agreed, among other things, to execute and deliver a written consent approving the Business Combination Agreement. The shares of Altus Common Stock that are subject to the Altus Stockholders Support Agreement represent over a majority of the outstanding voting power of Altus capital stock and are sufficient to obtain the requisite approvals needed from the Altus stockholders in connection with the transactions contemplated by the Business Combination Agreement. In addition, the Altus Stockholders Support Agreement contains restrictions on such Altus stockholders (a) transferring such shares of Altus Common Stock (subject to certain restrictions) and (b) soliciting or engaging in discussions or negotiations regarding alternative acquisition proposals.

Pursuant to the PIPE Subscription Agreements, CBAH has agreed to issue and sell to the PIPE Investors, and the PIPE Investors have agreed to buy from CBAH 27,500,000 shares of CBAH Class A common stock at a purchase price of $10.00 per share for an aggregate commitment of $275,000,000. The PIPE Investment is conditioned upon, among other conditions, and will be consummated concurrently with, the closing of the Merger.

It is anticipated that, upon completion of the business combination: (a) CBAH’s public stockholders (other than the PIPE Investors) will retain an ownership interest of approximately 25.3% in the post-combination company; (b) the PIPE Investors (other than the Sponsor Parties) will own approximately 12.8% of the post-combination company; (c) the Sponsor Parties will own approximately 5.3% of the post-combination company; (d) current holders of Altus Stock will own approximately 56.5% of the post-combination company (excluding shares purchased by current Altus stockholders in the PIPE Investment); and (e) Existing CBAH Directors will own approximately 0.1% of the post-combination company. These levels of ownership interest: (i) exclude the impact of the shares of CBAH Class A common stock underlying the warrants and the shares underlying the unvested RSUs to be issued pursuant to the Management Equity Incentive Letter, (ii) exclude the impact of the shares of CBAH Class A common stock reserved for issuance under the Incentive Plan and ESPP, (iii) assume that no CBAH public stockholder exercises redemption rights with respect to its shares for a pro rata portion of the funds in the trust account, (iv) assume that 90,000,000 shares of CBAH Class A common stock are issued as Merger Consideration and are outstanding as of the closing of the Merger and (v) include the 1,408,750 Alignment Shares that will be outstanding immediately following the closing of the Transactions (which Alignment Shares will be automatically converted into a number of CBAH Class A common stock based upon the Total Return on the CBAH Class A common stock as of the relevant measurement date over the seven fiscal years following the business combination. See “Description of CBAH’s Securities—Alignment Shares.”). The ownership interest of CBAH’s public stockholders (other than PIPE Investors) who elect not to redeem their shares may be diluted when considering all possible sources and extent of dilution. See the question “What equity stake will current stockholders of Altus, the PIPE Investors, CBAH’s public stockholders and the Sponsor hold in the post-combination company after the Closing?” within the section entitled “Questions and Answers.”

CBAH management and the Board considered various factors in determining whether to approve the Business Combination Agreement and the Transactions, including the Merger. For more information about the reasons that the Board considered in determining its recommendation, please see the section entitled “The Business Combination — CBAH’s Board of Directors’ Reasons for Approval of the Transactions.” When you consider the Board’s recommendation of these proposals, you should keep in mind that our directors and officers have interests in the business combination that are different from, or in addition to, the interests of CBAH stockholders generally. Please see the section entitled “The Business Combination — Interests of Certain Persons in the Business Combination” for additional information. The Board was aware of and considered these interests, among other matters, in evaluating and negotiating the Transactions and in recommending to the CBAH stockholders that they vote “FOR” the proposals presented at the special meeting.

At the special meeting, CBAH’s stockholders will be asked to consider and vote on the following proposals:

a proposal to approve the business combination described in this proxy statement/prospectus, including adopting the Business Combination Agreement and the Transactions described in this proxy statement/prospectus. Please see the section entitled “Proposal No. 1 — The Business Combination Proposal”;

proposals to approve and adopt the third amended and restated certificate of incorporation of CBAH. Please see the section entitled “Proposal No. 2 — The Charter Proposals”;

a proposal to vote upon, on a non-binding advisory basis, certain governance provisions in the third amended and restated certificate of incorporation, presented separately in accordance with requirements of the SEC. Please see the section entitled “Proposal No. 3 — The Governance Proposal”;

a proposal to approve and adopt the 2021 Omnibus Incentive Plan (the “Incentive Plan”) and the material terms thereunder, including the authorization of the initial share reserve thereunder. Please see the section entitled “Proposal No. 4 — The Incentive Plan Proposal”;

a proposal to approve and adopt the 2021 Employee Stock Purchase Plan (the “ESPP”) and the material terms thereunder, including the authorization of the initial share reserve thereunder. Please see the section entitled “Proposal No. 5 — The ESPP Proposal”;

a proposal to elect seven directors to serve staggered terms on the Board until immediately following the annual meeting of CBAH stockholders for the calendar year ended December 31, 2022, 2023 and 2024, as applicable and until their respective successors are duly elected and qualified. Please see the section entitled “Proposal No. 6 — The Director Election Proposal”;

a proposal to approve, for purposes of complying with the applicable provisions of Section 312.03 of the NYSE’s Listed Company Manual Rules, the issuance of (a) more than 20% of CBAH’s issued and outstanding shares of common stock in connection with the Transactions, including, without limitation, the issuance of shares of CBAH Class A common stock as Merger Consideration and the PIPE Investment (as described below), and the issuance of shares of CBAH Class A common stock to a Related Party (as defined in Section 312.03 of the NYSE’s Listed Company Manual) in connection with the Transactions. Please see the section entitled “Proposal No. 7 — The NYSE Proposal”;

a proposal to adjourn the special meeting to a later date or dates, if necessary, to permit further solicitation and vote of proxies in the event that there are insufficient votes for, or otherwise in connection with, the approval of the business combination proposal, the charter proposals, the governance proposal, the incentive plan proposal, the ESPP proposal, the director election proposal or the NYSE proposal. Please see the section entitled “Proposal No. 8 — The Adjournment Proposal.”

Upon consummation of the Transactions, the Board will initially consist of one Class B Director and three additional classes of directors. Each Class I director will have a term that expires immediately following CBAH’s annual meeting of stockholders for the calendar year ended December 31, 2022, each Class II director will have a term that expires immediately following CBAH’s annual meeting of stockholders for the year ended December 31, 2023, and each Class III director will have a term that expires immediately following CBAH’s annual meeting of stockholders for the calendar year ended December 31, 2024, or in each case until their respective successors are duly elected and qualified, or until their earlier resignation, removal or death. The Class I, Class II and Class III directors will be elected by the holders of the CBAH Class A common stock, voting separately as a class. The Class B Director will be elected by the holders of CBAH Class B common stock, voting separately as a class, at each annual meeting of the CBAH stockholders or other meeting held by CBAH for the election of directors or by written consent. Upon the conversion of all issued and outstanding shares of CBAH Class B common stock into shares of CBAH

Class A common stock, the position of Class B Director shall cease to exist, provided that the person who is the Class B Director at the time of such conversion will have the right to continue to serve on the Board until the next annual meeting of stockholders of CBAH, subject to proportionality requirements and earlier removal for cause or pursuant to the terms of the Investor Rights Agreement. The holders of the CBAH Class B common stock are expected to execute a written consent electing the Class B Director in connection with the consummation of the Transactions. The vote of the holders of CBAH Class A common stock is not being solicited with respect to the election of the Class B Director. Please see the sections entitled “Proposal No. 6 — The Director Election Proposal” and “Management After the Business Combination” for additional information.

Why am I receiving this proxy statement/prospectus?

CBAH and Altus have agreed to a business combination under the terms of the Business Combination Agreement that is described in this proxy statement/prospectus. A copy of the Business Combination Agreement is attached hereto as Annex A, and CBAH and Altus encourage their stockholders to read it in its entirety.

Why is CBAH proposing the business combination?

CBAH was formed solely for the purpose of effecting a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or similar business combination with one or more businesses.

What will happen in the business combination?

Pursuant to the Business Combination Agreement, and upon the terms and subject to the conditions set forth therein, CBAH will acquire Altus through the initial merger of First Merger Sub with and into Altus, with Altus as the surviving company, followed immediately thereafter by the merger of Altus with and into Second Merger Sub, with Second Merger Sub continuing as the surviving entity, which mergers we collectively refer to as the “Merger.”

Following the business combination, will CBAH’s securities continue to trade on a stock exchange?

Yes. We intend to apply to continue the listing of the CBAH Class A common stock and Redeemable Warrants on the NYSE. In connection with the business combination, CBAH will change its name to Altus Power, Inc. and the CBAH Class A common stock and Redeemable Warrants will begin trading on the NYSE under the symbols “AMPS” and “AMPS WS” respectively. As a result, our publicly traded SAIL^SM securities will separate into the component securities upon consummation of the business combination and will no longer trade as a separate security.

How will the business combination impact the shares of CBAH outstanding after the business combination?

As a result of the business combination and the consummation of the Transactions, including, without limitation, the PIPE Investment, the number of shares of CBAH Class A common stock outstanding will increase by approximately 292% to approximately 157,750,000 shares of CBAH Class A common stock (assuming that no shares of CBAH Class A common stock are elected to be redeemed by CBAH public stockholders and the other assumptions described under “Unaudited Pro Forma Condensed Combined Financial Information”). Additional shares of CBAH Class A common stock may be issuable in the future as a result of the issuance of additional shares that are not currently outstanding, including issuance of shares of CBAH Class A common stock upon exercise of the warrants and issuances under the Incentive Plan and ESPP. The issuance and sale of such shares in the public market could adversely impact the market price of the CBAH Class A common stock, even if our business is doing well. Pursuant to the Incentive Plan and the ESPP, copies of which are attached hereto as Annex E and Annex F, respectively, following the

What are the material U.S. federal income tax consequences of the business combination to a U.S. Holder of Altus Common Stock?

It is intended that the business combination qualifies as a “reorganization” within the meaning of Section 368(a) of the Code. Although it is not a condition to closing that an opinion of counsel regarding the tax treatment of the business combination be provided, Simpson Thacher & Bartlett LLP is providing an opinion that the business combination will qualify as a “reorganization” within the meaning of Section 368(a) of the Code. Such opinion is based on representations and assumptions as to factual matters made by Altus and CBAH and on current law. Assuming the business combination is treated as a reorganization within the meaning of Section 368(a) of the Code, a U.S. Holder that exchanges its Altus Common Stock for a combination of CBAH Common Stock and cash (other than any cash received in lieu of a fractional share of CBAH Common Stock) in a reorganization will generally recognize gain (but not loss) in an amount equal to the lesser of: (i) the amount of cash (other than cash received in lieu of fractional shares, if any) received by such holder in exchange for its Altus Common Stock in the business combination; and (ii) the excess, if any, of (a) the sum of the amount of cash (other than cash received in lieu of fractional shares, if any) plus the fair market value of the CBAH Common Stock at the Second Effective Time, as defined in the Business Combination Agreement, received by such holder in exchange for its Altus Common Stock in the business combination, over (b) such holder’s tax basis in its Altus Common Stock exchanged.

Will the management of Altus change in the business combination?

We anticipate that all of the executive officers of Altus will remain with the post-combination company. In addition, Gregg Felton, Lars Norell, Christine Detrick, Richard Peretz, Sharon Daley, Robert Horn and Sarah Coyne will each be nominated to serve as directors of CBAH following completion of the business combination. In addition, William Concannon is expected to be elected to serve as the Class B Director upon completion of the business combination. Please see the sections entitled “Proposal No. 6 — The Director Election Proposal” and “Management After the Business Combination” for additional information.

What equity stake will current stockholders of Altus, the PIPE Investors, CBAH’s public stockholders and the Sponsor hold in the post-combination company after the Closing?

The equity stakes of the current stockholders of Altus, the PIPE Investors, CBAH’s public stockholders and the Sponsor in the post-combination company after the Closing will vary based on a number of factors, including how many public stockholders elect to redeem their shares. To illustrate these parties’ equity interests under various scenarios, the following table shows (a) the impact of the shares of CBAH Class A common stock underlying the Redeemable Warrants and the Private Placement Warrants, (b) the impact of the shares of CBAH Class A common stock underlying the Private Placement Warrants issued to the Sponsor in connection with the Sponsor’s settlement of the second amended and restated promissory note (See “Related Party Notes” within the section entitled “Certain Relationships and Related Person Transactions”), (c) the impact of the shares underlying the unvested RSUs to be issued pursuant to the Management Equity Incentive Letter, and (d) the impact of the maximum number of shares of CBAH Class A common stock into which the Alignment Shares may convert. The table below presents four alternative redemption scenarios: (i) no public stockholders of CBAH exercise their redemption rights (No Redemption Scenario), (ii) stockholders holding 13,282,500 public shares (33% of maximum redemption) exercise their redemption rights (Low Redemption Scenario), (iii) stockholders holding 26,565,000 public shares (66% of maximum redemption) exercise their redemption rights (High Redemption Scenario), and (iv) all public stockholders of CBAH exercise their redemption rights (Maximum Redemption Scenario).

The number of shares of CBAH Class A common stock issuable upon conversion of the Alignment Shares is based on the performance of the post-combination company stock price, resulting in a possible range of 14,091 to 13,408,750 shares under the No Redemption Scenario, 14,091 to 14,986,250 shares under the Low Redemption Scenario, 14,091 to 13,887,575 shares under the High Redemption Scenario, and 14,091 to 12,587,500 shares under the Maximum Redemption Scenario. The table presented above illustrates the most dilutive effect of the Alignment Shares by including the maximum number of shares of CBAH Class A common stock issuable in each scenario.

Under the terms of the second amended and restated promissory note between CBAH and the Sponsor, the Sponsor has the option to settle the note in either cash or through a conversion into Private Placement Warrants at a ratio of one whole warrant per $1.50 in principal amount. The outstanding balance of the note as of June 30, 2021 was $1.1 million. On August 12, 2021, the Company borrowed an additional $1.9 million under the note, for total outstanding borrowings of $3.0 million. The table

Will CBAH obtain new financing in connection with the Transactions?

Yes. CBAH has entered into subscription agreements with the PIPE Investors, pursuant to which CBAH has agreed to issue and sell to the PIPE Investors and the PIPE Investors have agreed to purchase from CBAH 27,500,000 shares of CBAH Class A common stock at a purchase price per share of $10.00 and an aggregate purchase price of $275,000,000. In the event that the aggregate amount of cash available in the CBAH trust account (net of redemptions) and PIPE Investment proceeds (including any exercise of the Backstop Commitment) are less than $677.5 million in the aggregate, Altus, New Altus, or either of their respective subsidiaries, may seek additional financing in connection with the repayment of the Altus Series A redeemable preferred stock and may elect to enter into new debt financing arrangements with one or more third parties (which parties may be affiliated with The Blackstone Group, Inc.). In the event such debt financing is entered into, it is expected to be (i) in an amount not to exceed the aggregate redemption price of the Altus Series A redeemable preferred stock and (ii) on economic terms no less favorable than those of the Altus Series A redeemable preferred stock. If applicable, we may choose to fund all or a portion of the redemption of the Altus Series A redeemable preferred stock on the Closing Date with cash on hand and we may not negotiate and enter into such new debt financing until after the Closing Date. There can be no assurance that such new debt financing in the amount we are seeking will be available at such time or if the economic and other terms thereof will be more favorable than those of the Altus Series A redeemable preferred stock. Please see the section entitled “The Business Combination — Sources and Uses for the Business Combination.”

What conditions must be satisfied to complete the business combination?

There are a number of closing conditions in the Business Combination Agreement, including the approval by the stockholders of CBAH of the business combination proposal, the NYSE proposal, the charter proposals, the incentive plan proposal and the ESPP proposal. In addition, Altus’s stockholders must adopt the Business Combination Agreement and thereby approve the Transactions, including the Business Combination Agreement. For a summary of the conditions that must be satisfied or waived prior to completion of the business combination, please see the section entitled “The Business Combination Agreement — Conditions to Closing.”

Are there any arrangements to help ensure that CBAH will have sufficient funds, together with the proceeds in its trust account and from the PIPE Investment, to consummate the Transactions?

While the Merger Consideration consists entirely of securities of CBAH, the Business Combination Agreement provides that the consummation of the Transactions is conditioned upon, among other things, (a) after taking into account the PIPE Investment and after giving effect to exercise by the holders of the public shares of their right to redeem their shares of CBAH Class A common stock into their pro rata share of the trust account in accordance with CBAH’s certificate of incorporation, at Closing and without giving effect to any of the other Transactions (and without deducting expenses related to the Transactions that are to be paid at or after Closing), CBAH having at least $425,000,000 in available cash and (b) CBAH having at least $5,000,001 of net tangible assets (as determined in accordance with Rule 3a51-1(g)(1) under the Exchange Act) taking into account the proceeds of the equity financing.

When do you expect the business combination to be completed?

It is currently anticipated that the business combination will be consummated promptly following the CBAH special meeting which is set for December 6, 2021, subject to the satisfaction of the closing conditions; however, such meeting could be adjourned, as described herein. For a description of the conditions to the closing of the business combination, please see the section entitled “The Business Combination Agreement — Conditions to Closing.”

What do I need to do now?

CBAH urges you to read carefully and consider the information contained in this proxy statement/prospectus, including the Annexes, and to consider how the business combination will affect you as a stockholder and/or warrant holder of CBAH. CBAH stockholders should then vote as soon as possible in accordance with the instructions provided in this proxy statement/prospectus and on the enclosed proxy card or, if you hold your shares through a brokerage firm, bank or other nominee, on the voting instruction form provided by the broker, bank or other nominee.

When and where is the Special Meeting?

The special meeting will be held via live webcast on December 6, 2021 at 10:00 a.m. (New York City time). The special meeting can be accessed by visiting https://www.cstproxy.com/cbreacquisitionholdings/2021 where you will be able to listen to the meeting live and vote during the meeting. Please note that you will only be able to access the special meeting by means of remote communication.

What are the proposals on which I am being asked to vote at the special meeting?

The stockholders of CBAH will be asked to consider and vote on the following proposals at the special meeting:

a proposal to approve the business combination described in this proxy statement/prospectus, including adopting the Business Combination Agreement and approving the Transactions described in this proxy statement/prospectus. Please see the section entitled “Proposal No. 1 — The Business Combination Proposal”;

proposals to approve and adopt the third amended and restated certificate of incorporation of CBAH. Please see the section entitled “Proposal No. 2 — The Charter Proposals”;

a proposal to vote upon, on a non-binding advisory basis, certain governance provisions in the third amended and restated certificate of incorporation, presented separately, in accordance with the requirements of the SEC. Please see the section entitled “Proposal No. 3 — The Governance Proposal”;

a proposal to approve and adopt the Incentive Plan and the material terms thereunder, including the authorization of the initial share reserve thereunder. Please see the section entitled “Proposal No. 4 — The Incentive Plan Proposal”;

a proposal to approve and adopt the ESPP and the material terms thereunder, including the authorization of the initial share reserve thereunder. Please see the section entitled “Proposal No. 5 — The ESPP Proposal”;

a proposal to elect seven directors to serve staggered terms on the Board until immediately following the annual meeting of CBAH stockholders for the calendar year ended December 31, 2022, 2023 and 2024, as applicable and until their respective successors are duly elected and qualified. Please see the section entitled “Proposal No. 6 — The Director Election Proposal”;

a proposal to approve, for purposes of complying with the applicable provisions of Section 312.03 of the NYSE’s Listed Company Manual Rules, the issuance of (a) more than 20% of CBAH’s issued and outstanding shares of common stock in connection with the Transactions, including, without limitation, the issuance of shares of CBAH Class A common stock as Merger Consideration and the PIPE Investment (as described below), and (b) shares of CBAH Class A common stock to a Related Party (as defined in Section 312.03 of the NYSE’s Listed Company Manual) in connection with the Transactions. Please see the section entitled “Proposal No. 7 — The NYSE Proposal”;

a proposal to adjourn the special meeting to a later date or dates, if necessary, to permit further solicitation and vote of proxies in the event that there are insufficient votes for, or otherwise in connection with, the approval of the business combination proposal, the charter proposals, the governance proposal, the incentive plan proposal, the ESPP proposal, the director election proposal or the NYSE proposal. Please see the section entitled “Proposal No. 8 — The Adjournment Proposal.”

Why is CBAH providing stockholders with the opportunity to vote on the business combination?

Under CBAH’s current certificate of incorporation, we must provide all holders of public shares with the opportunity to have their public shares redeemed upon the consummation of our initial business combination either in conjunction with a tender offer or in conjunction with a stockholder vote. For business and other reasons, including those described under “Proposal No. 7 — The NYSE Proposal,” we have elected to provide our stockholders with the opportunity to have their public shares redeemed in connection with a stockholder vote rather than a tender offer. Therefore, we are seeking to obtain the approval of our stockholders of the business combination proposal in order to allow our public stockholders to effectuate redemptions of their public shares in connection with the closing of the business combination.

What constitutes a quorum at the special meeting?

A majority of the voting power of all issued and outstanding shares of CBAH common stock entitled to vote as of the record date at the special meeting must be present via the virtual meeting platform, or represented by proxy, at the special meeting to constitute a quorum and in order to conduct business at the special meeting. Abstentions will be counted as present for the purpose of determining a quorum. As of the record

What vote is required to approve the proposals presented at the special meeting?

The affirmative vote of the holders of a majority of the voting power of the outstanding shares of (x) CBAH Class B common stock, voting separately as a single class, in person or represented by proxy and entitled to vote thereon, and (y) CBAH common stock, voting together as a single class, in person or represented by proxy and entitled to vote thereon, is required to approve: “Proposal No. 1 — The Business Combination Proposal”; “Proposal No. 3 — The Governance Proposal”; “Proposal No. 4 — The Incentive Plan Proposal”; “Proposal No. 5 — The ESPP Proposal”; and “Proposal No. 7 — The NYSE Proposal,” in each case, assuming a quorum is present. The approval of “Proposal No. 2 — The Charter Proposals” requires the affirmative vote of holders of a majority of the voting power of the outstanding shares of (i) CBAH common stock entitled to vote thereon, voting together as a single class, and (ii) CBAH Class B common stock, voting separately as a single class, in person or represented by proxy and entitled to vote thereon. Furthermore, the affirmative vote of the holders of a majority of the outstanding shares of CBAH common stock not owned, directly or indirectly by (i) CBRE Group, Inc. or any of its affiliates including the Sponsor or (ii) any executive officer of CBAH (such outstanding shares, the “Unaffiliated Stock”), voting separately as a single class, in person or represented by proxy and entitled to vote thereon, is required to approve “Proposal No. 1 — The Business Combination Proposal;” and “Proposal No. 3 — The Governance Proposal” (the “CBAH Unaffiliated Stockholder Approval”). The approval of “Proposal No. 8 — The Adjournment Proposal” requires the affirmative vote of the holders of a majority of the voting power of the outstanding shares of CBAH Class A common stock and CBAH Class B common stock, voting together as a single class, in person or represented by proxy and entitled to vote thereon, assuming a quorum is present.

How many votes do I have at the special meeting?

CBAH stockholders are entitled to one vote on each proposal presented at the special meeting for each share of common stock held of record as of October 27, 2021, the record date for the special meeting. As of 5:00

Who gets to elect the Class B Director?

Only holders of shares of the CBAH Class B common stock are entitled to vote for the Class B Director. The CBAH Class B common stock is not publicly traded and all outstanding shares are held by the Sponsor and CBAH’s current officers and directors. The holders of the CBAH Class B common stock are expected to act by written consent to elect the Class B Director in connection with the consummation of the Transactions. This document serves as an information statement with respect to that action by the holders of the CBAH Class B common stock. The vote of the holders of CBAH Class A common stock is not being sought for the election of the Class B Director.

What happens if I sell my shares of CBAH Class A common stock before the special meeting?

The record date for the special meeting is earlier than the date that the business combination is expected to be completed. If you transfer your shares of CBAH Class A common stock after the record date, but before the special meeting, unless the transferee obtains from you a proxy to vote those shares, you will retain your right to vote at the special meeting. However, you will not be able to seek redemption of your shares of CBAH Class A common stock because you will no longer be able to deliver them for cancellation upon consummation of the business combination. If you transfer your shares of CBAH Class A common stock prior to the record date, you will have no right to vote those shares at the special meeting or redeem those shares for a pro rata portion of the proceeds held in our trust account.

Why is CBAH proposing the governance proposal?

As required by applicable SEC guidance, CBAH is requesting that its stockholders vote upon, on a non-binding advisory basis, a proposal to approve certain governance provisions contained in the third amended and restated certificate of incorporation that materially affect stockholder rights. This separate vote is not otherwise required by Delaware law separate and apart from the charter proposals, but pursuant to SEC guidance, CBAH is required to submit these provisions to its stockholders separately for approval. However, the stockholder vote regarding this proposal is an advisory vote, and is not binding on CBAH or the Board (separate and apart from the approval of the charter proposals). Furthermore, the business combination is not conditioned on the separate approval of the governance proposal (separate and apart from approval of the charter proposals). Please see the section entitled “Proposal No. 3 — The Governance Proposal.”

Did the Board obtain a third-party valuation or fairness opinion in determining whether or not to proceed with the business combination?

Yes, the Special Committee and the Board received a fairness opinion from the Special Committee’s financial advisor, Duff & Phelps. For more information on the fairness opinion, see “The Business Combination — Opinion of Duff & Phelps, the Financial Advisor to the Special Committee of the CBAH Board.”

Does the Sponsor and/or any of the CBAH directors or officers have interests in the business combination proposal and the other proposals that may differ from or be in addition to the interests of CBAH’s stockholders?

The Sponsor, CBAH’s executive officers and directors may have interests in the business combination proposal and the other proposals that may be different from, or in addition to, the interests of CBAH’s stockholders generally. These interests may cause the Sponsor and the directors and executive officers of CBAH to view the business combination proposal and the other proposals differently than CBAH’s

Do I have redemption rights?

If you are a holder of public shares, you have the right to demand that CBAH redeem such shares for a pro rata portion of the cash held in CBAH’s trust account. CBAH sometimes refers to these rights to demand redemption of the public shares as “redemption rights.”

How do I exercise my redemption rights?

If you are a holder of public shares and wish to exercise your redemption rights, you must, no later than 5:00 p.m. (New York City time) on December 2, 2021 (two (2) business days prior to the date of the special meeting):

submit a written request to CBAH’s transfer agent that CBAH redeem your public shares for cash,

certify in such demand for redemption that you “ARE” or “ARE NOT” acting in concert or as a “group” (as defined in Section 13d-3 of the Exchange Act), and

deliver such public shares to CBAH’s transfer agent (physically or electronically using the Depository Trust Company’s DWAC (Deposit and Withdrawal at Custodian) system).

Do I have appraisal rights if I object to the proposed business combination?

No. Neither CBAH stockholders nor its SAIL^SM securityholders or its warrant holders have appraisal rights in connection with the business combination under the DGCL.

What happens to the funds deposited in the trust account after consummation of the business combination?

The net proceeds of the CBAH IPO and the sale of the Private Warrants, a total of $402,500,000, were placed in the trust account immediately following the CBAH IPO. After consummation of the business combination, the funds in the trust account will be used to pay holders of the public shares who exercise redemption rights, to pay fees and expenses incurred in connection with the business combination (including aggregate fees of $14,087,500 as deferred underwriting commissions) and to fund future growth of the post-combination company. Please see the section entitled “The Business Combination — Sources and Uses for the Business Combination.”

What happens if a substantial number of public stockholders vote in favor of the business combination proposal and exercise their redemption rights?

CBAH’s public stockholders may vote in favor of the business combination and still exercise their redemption rights. Accordingly, the business combination may be consummated even though the funds available from the trust account and the number of public stockholders are substantially reduced as a result of redemptions by public stockholders. In the event a substantial number of public stockholders vote in favor of the business combination proposal and exercise their redemption rights, fewer funds in the trust account will be available to the post-combination company to fund future growth.

What happens if the business combination is not consummated?

If CBAH does not complete the business combination with Altus for whatever reason, CBAH would search for another target business with which to complete a business combination. If CBAH does not complete a business combination with Altus or another target business by December 15, 2022 (or February 15, 2023 if CBAH has entered into an agreement for its initial business combination by December 15, 2022), CBAH must redeem 100% of the outstanding public shares, at a per-share price, payable in cash, equal to the amount then held in the trust account divided by the number of outstanding public shares. The Sponsor and CBAH’s officers and directors have entered into a letter agreement with CBAH, pursuant to which they have waived their rights to liquidating distributions from the trust account with respect to their Alignment Shares if CBAH fails to complete its initial business combination within the applicable window period. As a result, the Alignment Shares will be worthless if a business combination is not completed during the applicable completion window. Additionally, in the event of such liquidation, there will be no distribution with respect to CBAH’s outstanding warrants. Accordingly, the warrants will be worthless.

How do the Sponsor Parties intend to vote on the proposals?

The Sponsor Parties own of record and are entitled to vote an aggregate of 1,932,000 shares of CBAH Class B common stock (or 19.2% of the aggregate voting power of CBAH common stock as of the record date). Other than Robert E. Sulentic, who beneficially owns 10,000 shares of CBAH Class A common stock, none of CBAH’s directors and officers own any public shares as of the date hereof. For more information regarding director ownership of securities, please see the section entitled “Beneficial Ownership of Securities.” The Sponsor Parties have agreed to vote any shares of CBAH common stock held by them as of the record date, in favor of the Transactions. The Sponsor Parties may have interests in the business combination that may conflict with your interests as a stockholder. Please see the sections entitled “Summary — Interests of Certain Persons in the Business Combination” and “The Business Combination — Interests of Certain Persons in the Business Combination.”

When and where is the Special Meeting?

The Special Meeting will be held at 10:00 a.m. New York City time, on December 6, 2021, in virtual format. The Company’s Stockholders may attend, vote and examine the list of Stockholders entitled to vote at the Special Meeting by visiting https://www.cstproxy.com/cbreacquisitionholdings/2021 and entering the control number found on their proxy card, voting instruction form or notice included in their proxy materials. You may also attend the meeting telephonically by dialing 1-877-770-3647 (toll-free within the United States and Canada) or +1 312-780-0854 (outside of the United States and Canada, standard rates apply). The passcode for telephone access is 67297108#, but please note that you will not be able to vote or ask questions if you choose to participate telephonically. In light of public health concerns regarding the COVID-19 pandemic, the Special Meeting will be held in virtual meeting format only. You will not be able to attend the Special Meeting in person.

How do I attend a virtual Special Meeting?

As a registered shareholder, you received a Proxy Card from Continental Stock Transfer. The form contains instructions on how to attend the virtual Special Meeting including the URL address, along with your control number. You will need your control number for access. If you do not have your control number, contact Continental Stock Transfer at the phone number or e-mail address below. Continental Stock Transfer support contact information is as follows: 917-262-2373, or email proxy@continentalstock.com.

How do I vote?

The special meeting will be held via live webcast at 10:00 a.m. (New York City time) on December 6, 2021. The special meeting can be accessed by visiting https://www.cstproxy.com/cbreacquisitionholdings/2021 where you will be able to listen to the meeting

If my shares are held in “street name,” will my broker, bank or nominee automatically vote my shares for me?

No. Under the rules of various national and regional securities exchanges, your broker, bank or nominee cannot vote your shares with respect to non-routine matters unless you provide instructions on how to vote in accordance with the information and procedures provided to you by your broker, bank or nominee. We believe the proposals presented to the stockholders at the special meeting will be considered non-routine and, therefore, your broker, bank or nominee cannot vote your shares without your instruction on any of the proposals presented at the special meeting. If you do not provide instructions with your proxy, your broker, bank or other nominee may deliver a proxy card expressly indicating that it is NOT voting your shares; this indication that a broker, bank or nominee is not voting your shares is referred to as a “broker non-vote.” Broker non-votes will not be counted for the purposes of determining the existence of a quorum or for purposes of determining the number of votes cast at the special meeting. Your bank, broker or other nominee can vote your shares only if you provide instructions on how to vote. You should instruct your broker to vote your shares in accordance with directions you provide.

How will a broker non-vote impact the results of each proposal?

Broker non-votes will count as a vote “AGAINST” the charter proposals but will not have any effect on the outcome of any other proposals.

May I change my vote after I have mailed my signed proxy card?

Yes. Stockholders of record may send a later-dated, signed proxy card to CBAH’s transfer agent at the address set forth at the end of this section so that it is received prior to the vote at the special meeting or attend the special meeting and vote. Stockholders also may revoke their proxy by sending a notice of revocation to CBAH’s Secretary, which must be received prior to the vote at the special meeting.

What happens if I fail to take any action with respect to the special meeting?

If you fail to take any action with respect to the special meeting and the business combination is approved by stockholders, the business combination will be consummated in accordance with the terms of the Business Combination Agreement. If you fail to take any action with respect to the special meeting and the business combination is not approved, we will not consummate the business combination.

What will happen if I sign and return my proxy card without indicating how I wish to vote?

Signed and dated proxies received by us without an indication of how the stockholder intends to vote on a proposal will be voted “FOR” each proposal presented to the stockholders. The proxyholders may use their discretion to vote on any other matters which properly come before the special meeting.

What should I do if I receive more than one set of voting materials?

Stockholders may receive more than one set of voting materials, including multiple copies of this proxy statement/prospectus and multiple proxy cards or voting instruction cards. For example, if you hold your shares in more than one brokerage account, you will receive a separate voting instruction card for each brokerage account in which you hold shares. If you are a holder of record and your shares are registered in more than one name, you will receive more than one proxy card. Please complete, sign, date and return each proxy card and voting instruction card that you receive in order to cast a vote with respect to all of your CBAH shares.

Who can help answer my questions?

If you have questions about the proposals to be voted on at the Special Meeting or if you need additional copies of the proxy statement or the enclosed proxy card you should contact: