Note 1 — Description of Organization and Business Operations

Organization and General

HH&L Acquisition Co. (the “Company”) was incorporated as a Cayman Islands exempted company on September 4, 2020. The Company was formed for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses or entities (the “Business Combination”).

As of December 31, 2022, the Company had not commenced any operations. All activity for the period from September 4, 2020 (inception) through December 31, 2022 relates to the Company’s formation and the initial public offering (the “Initial Public Offering”) described below, and since its Initial Public Offering its search for a Business Combination. The Company will not generate any operating revenues until after the completion of its initial Business Combination, at the earliest. The Company generates non-operating income from its investments held in the Trust Account funded by the proceeds of the Initial Public Offering.

The Company’s sponsor is HH&L Investment Co., a Cayman exempted company (the “Sponsor”). The registration statement for the Company’s Initial Public Offering was declared effective on February 4, 2021. On February 9, 2021, the Company consummated its Initial Public Offering of 41,400,000 units (the “Units” and, with respect to the Class A ordinary shares included in the Units being offered, the “Public Shares”), including 5,400,000 additional Units to cover over-allotments (the “Over-Allotment Units”), at $10.00 per Unit, generating gross proceeds of $414.0 million, and incurring offering costs of approximately $23.7 million, of which approximately $14.5 million was for deferred underwriting commissions. On October 7, 2022, one of the underwriters waived its entitlement to their deferred fee of approximately $8.7 million. On October 13, 2022, the remaining underwriter has waived entitlement to their deferred fee only with respect to the Proposed Business Combination as defined below. See Note 5.

Simultaneously with the closing of the Initial Public Offering, the Company consummated the private placement (“Private Placement”) of 10,280,000 warrants (each, a “Private Placement Warrant” and collectively, the “Private Placement Warrants”), at a price of $1.00 per Private Placement Warrant with the Sponsor, generating gross proceeds of approximately $10.3 million (see Note 4).

Upon the closing of the Initial Public Offering and the Private Placement, a total of $414.0 million ($10.00 per Unit) of the net proceeds of the Initial Public Offering and certain of the proceeds of the Private Placement was placed in a trust account (“Trust Account”), located in the United States with Continental Share Transfer & Trust Company acting as trustee, and is invested only in United States “government securities” within the meaning of Section 2(a)(16) of the Investment Company Act of 1940, as amended, or the Investment Company Act, having a maturity of 185 days or less or in money market funds meeting certain conditions under Rule 2a-7 promulgated under the Investment Company Act which invest only in direct U.S. government treasury obligations, until the earlier of: (i) the completion of a Business Combination and (ii) the distribution of the Trust Account as described below.

The Company’s management has broad discretion with respect to the specific application of the net proceeds of the Initial Public Offering and the sale of Private Placement Warrants, although substantially all of the net proceeds are intended to be applied generally toward consummating a Business Combination. There is no assurance that the Company will be able to complete a Business Combination successfully. The Company must complete one or more initial Business Combinations having an aggregate fair market value of at least 80% of the assets held in the Trust Account (excluding the deferred underwriting commissions and taxes payable, if any, on income earned on the Trust Account) at the time of the agreement to enter into the initial Business Combination. Additionally, pursuant to NYSE rules, any business combination must be approved by a majority of our independent directors until the 80% of net assets test described above is satisfied. However, the Company will only complete a Business Combination if the post-transaction company owns or acquires 50% or more of the outstanding voting securities of the target or otherwise acquires a controlling interest in the target sufficient for it not to be required to register as an investment company under the Investment Company Act 1940, as amended (the “Investment Company Act”).

The Company will provide the holders of its Public Shares (the “Public Shareholders”) with the opportunity to redeem all or a portion of their Public Shares upon the completion of a Business Combination either (i) in connection with a shareholder meeting called to approve the Business Combination or (ii) by means of a tender offer. The decision as to whether the Company will seek shareholder approval of a Business Combination or conduct a tender offer will be made by the Company, solely in its discretion. The Public Shareholders will be entitled to redeem their Public Shares for a pro rata portion of the amount then in the Trust Account (initially at $10.00 per Public Share). The per-share amount to be distributed to Public Shareholders who redeem their Public Shares will not be reduced by the deferred underwriting commissions the Company will pay to the underwriter (as discussed in Note 5). These Public Shares were classified as temporary equity upon the completion of the Initial Public Offering in accordance with the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) Topic 480 “Distinguishing Liabilities from Equity” (ASC 480). In such case, the Company will proceed with a Business Combination if the Company has net tangible assets of at least $5,000,001 upon such consummation of a Business Combination and a majority of the shares voted are voted in favor of the Business Combination. If a shareholder vote is not required by law and the Company does not decide to hold a shareholder vote for business or other legal reasons, the Company will, pursuant to the amended and restated memorandum and articles of association (as may be amended from time to time, the “Charter”) which the Company has adopted upon the consummation of the Initial Public Offering (the “Amended and Restated Memorandum and Articles of Association”), conduct the redemptions pursuant to the tender offer rules of the U.S. Securities and Exchange Commission (“SEC”) and file tender offer documents with the SEC prior to completing a Business Combination. If, however, shareholder approval of the transactions is required by law, or the Company decides to obtain shareholder approval for business or legal reasons, the Company will offer to redeem shares in conjunction with a proxy solicitation pursuant to the proxy rules and not pursuant to the tender offer rules. Additionally, each Public Shareholder may elect to redeem their Public Shares irrespective of whether they vote for or against the proposed transaction. If the Company seeks shareholder approval in connection with a Business Combination, the initial shareholders (as defined below) agreed to vote their Founder Shares (as defined below in Note 4) and any Public Shares purchased during or after the Initial Public Offering in favor of a Business Combination. Subsequent to the consummation of the Initial Public Offering, the Company adopted an insider trading policy which will require insiders to: (i) refrain from purchasing shares during certain blackout periods and when they are in possession of any material non-public information and (ii) to clear all trades with the Company’s legal counsel prior to execution. In addition, the initial shareholders agreed to waive their redemption rights with respect to their Founder Shares and Public Shares in connection with the completion of a Business Combination.

Notwithstanding the foregoing, the Amended and Restated Memorandum and Articles of Association will provide that a Public Shareholder, together with any affiliate of such shareholder or any other person with whom such shareholder is acting in concert or as a “group” (as defined under Section 13 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), will be restricted from redeeming its shares with respect to more than an aggregate of 20% or more of the Class A ordinary shares sold in the Initial Public Offering, without the prior consent of the Company.

The Company’s Sponsor, officers and directors (the “initial shareholders”) agreed not to propose an amendment to the Amended and Restated Memorandum and Articles of Association (A) that would modify the substance or timing of the Company’s obligation to allow redemptions in connection with the initial Business Combination or to redeem 100% of its Public Shares if the Company does not complete a Business Combination by May 9, 2023, assuming the board of the Company has taken appropriate actions in accordance with the Extension Amendment Proposal, initially within 24 months (the “Combination Period”) or (B) with respect to any other provision relating to shareholders’ rights or pre-initial Business Combination activity, unless the Company provides the Public Shareholders with the opportunity to redeem their Public Shares in conjunction with any such amendment.

Pursuant to the second amended and restated memorandum and articles of association, as amended on February 7, 2023, if the Company is unable to complete the initial Business Combination by May 9, 2023, assuming the board of the Company has taken appropriate actions in accordance with the Extension Amendment Proposal, the Company will (i) cease all operations except for the purpose of winding up, (ii) as promptly as reasonably possible but no more than ten business days thereafter, redeem the public shares, at a per-share price, payable in cash, equal to the aggregate amount then on deposit in the trust account, including interest earned on the funds held in the trust account (less taxes payable and up to $100,000 of interest to pay dissolution expenses), divided by the number of then outstanding public shares, which redemption will completely extinguish public shareholders’ rights as shareholders (including the right to receive further liquidation distributions, if any), subject to applicable law and (iii) as promptly as reasonably possible following such redemption, subject to the approval of the remaining shareholders and the board of directors, liquidate and dissolve, subject in the case of clauses (ii) and (iii) to the Company obligations under Cayman Islands law to provide for claims of creditors and in all cases subject to the other requirements of applicable law. The Sponsor, officers and directors have entered into a letter agreement with the Company, pursuant to which they have agreed to waive their rights to liquidating distributions from the trust account with respect to their founder shares if the Company fails to complete the initial Business Combination by May 9, 2023, assuming the board of the Company has taken appropriate actions in accordance with the Extension Amendment Proposal. However, if the Sponsor or management team acquire

public shares after our initial public offering, they will be entitled to liquidating distributions from the trust account with respect to such public shares if the Company fails to complete the initial Business Combination within the prescribed time period.

The Company’s Sponsor, officers and directors have agreed to waive their liquidation rights with respect to the Founder Shares if the Company fails to complete a Business Combination within the Combination Period. However, if the Initial Shareholders or members of the Company’s management team acquire Public Shares in or after the Initial Public Offering, they will be entitled to liquidating distributions from the Trust Account with respect to such Public Shares if the Company fails to complete a Business Combination within the Combination Period. The underwriters have agreed to waive their rights to its deferred underwriting commission (see Note 5) held in the Trust Account in the event the Company does not complete a Business Combination within in the Combination Period and, in such event, such amounts will be included with the other funds held in the Trust Account that will be available to fund the redemption of the Public Shares. In the event of such distribution, it is possible that the per share value of the residual assets remaining available for distribution (including Trust Account assets) will be only $10.00 per share initially held in the Trust Account. In order to protect the amounts held in the Trust Account, the Sponsor has agreed to be liable to the Company if and to the extent any claims by a vendor for services rendered or products sold to the Company, or a prospective target business with which the Company has discussed entering into a transaction agreement, reduce the amount of funds in the Trust Account. This liability will not apply with respect to any claims by a third party who executed a waiver of any right, title, interest or claim of any kind in or to any monies held in the Trust Account or to any claims under the Company’s indemnity of the underwriters of the Initial Public Offering against certain liabilities, including liabilities under the Securities Act of 1933, as amended (the “Securities Act”). Moreover, in the event that an executed waiver is deemed to be unenforceable against a third party, the Sponsor will not be responsible to the extent of any liability for such third-party claims. The Company will seek to reduce the possibility that the Sponsor will have to indemnify the Trust Account due to claims of creditors by endeavoring to have all vendors, service providers (except for the Company’s independent registered public accounting firm), prospective target businesses or other entities with which the Company does business, execute agreements with the Company waiving any right, title, interest or claim of any kind in or to monies held in the Trust Account.

Proposed Business Combination

On October 14, 2022, the Company entered into a Business Combination Agreement (the “Business Combination Agreement”) by and among the Company, Diamond Merger Sub Inc., a Delaware corporation and a direct wholly owned subsidiary of the Company (“Merger Sub”), and DiaCarta, Ltd., a Cayman Islands exempted company limited by shares (“DiaCarta”), as fully disclosed in a Current Report on Form 8-K as filed with the SEC by the Company on October 14, 2022.

Pursuant to the terms of the Business Combination Agreement, a business combination between the Company and DiaCarta (the “Proposed Business Combination”) will be effected in two steps. First, before the closing of the Proposed Business Combination (the “Closing”), both the Company and DiaCarta will deregister in the Cayman Islands and domesticate as Delaware corporations in accordance with Section 388 of the Delaware General Corporation Law and the Cayman Islands Companies Act (As Revised), with DiaCarta changing its name to DiaCarta Holdings, Inc. (the “Domestication”). Second, at the Closing, Merger Sub will merge with and into DiaCarta Holdings, Inc., with DiaCarta Holdings, Inc. surviving such merger as the surviving entity (the “Merger”). Upon consummation of the Proposed Business Combination, DiaCarta Holdings, Inc. will become a wholly owned subsidiary of the Company. The Company will then change its name to “DiaCarta, Inc.” We refer to the Company after the Domestication but before the Merger as “Domesticated SPAC.” The aggregate merger consideration paid to DiaCarta equityholders in connection with the Proposed Business Combination consists of 46 million shares of Domesticated SPAC Common Stock, which is calculated based on a pre-money equity valuation of DiaCarta at $460.0 million on a fully diluted basis.

The obligations of the parties (or, in some cases, some of the parties) to consummate the Proposed Business Combination are subject to the satisfaction or waiver of certain customary closing conditions of the respective parties, including, among others: (i) the accuracy of representations and warranties to various standards, from no material qualifier to a material adverse effect qualifier, (ii) material compliance with pre-closing covenants, (iii) no material adverse effect both for the Company and DiaCarta and its subsidiaries, (iv) the delivery of customary closing certificates, (v) the waiting period of periods required by any Antitrust Authorities (as defined under the Business Combination Agreement) and any other Governmental Approvals (as defined under the Business Combination Agreement) shall have been obtained, expired or been terminated, as applicable, (vi) the absence of a legal prohibition on consummating the transactions, (vii) approval by the Company’s and DiaCarta’s shareholders, (viii) approval of the listing on the NYSE for newly issued shares, and (ix) the Company having at least $5,000,001 of net tangible assets remaining after redemption.

In connection with the Business Combination, the Company entered into an engagement with a third party who will act as its financial advisor and its capital market advisor and placement agent in connection with the Proposed Business Combination. The fee arrangement consists of a $4.0 million advisor fee and an offering fee of 4.0% of the sum of the gross proceeds raised by the third party. The fees are

contingent upon the closing of the transaction and private placement. As prescribed by the arrangement, in the Company’s sole discretion, it may elect to pay the $2.0 million of the advisor fee with ordinary shares of the publicly listed post-business combination company.

The Company has agreed, pursuant to the Business Combination Agreement, to seek additional investors through one or more private placements of common stock of the Domesticated SPAC. In connection with the Proposed Business Combination, the Sponsor has agreed to contribute or forfeit certain Class B Ordinary Shares owned by itself to facilitate financing after signing of the Business Combination Agreement and certain forfeiture arrangement with an agreed cap.

The full Business Combination Agreement and other agreements entered into or contemplated to be executed prior to the Closing have been filed on a Current Report on Form 8-K filed with the SEC on October 14, 2022. In addition, the Company has filed a Registration Statement on Form S-4/A on January 23, 2023 with respect to the Proposed Business Combination.