Exhibit 4.5

DESCRIPTION OF THE REGISTRANT’S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED

As of December 31, 2024, HCM II Acquisition Corp. (“we,” “our,” “us” or “Company”) had the following three classes of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”): our (i) units, consisting of one Class A Ordinary Share (as defined below, the “Public Shares”) and one-half of one redeemable Warrant (as defined below), with each whole Warrant entitling the holder thereof to purchase one Class A Ordinary Share (the “Units”), (ii) Class A ordinary shares, $0.0001 par value per share (the “Class A Ordinary Shares”), and (iii) public warrants, with each whole warrant exercisable for one Class A Ordinary Share for $11.50 per share (the “Warrants”). Pursuant to our amended and restated memorandum and articles of association, as amended and currently in effect (the “Amended and Restated Charter”), our authorized capital stock consists of 220,000,000 Ordinary Shares, including 200,000,000 Class A Ordinary Shares and 20,000,000 Class B ordinary shares, $0.0001 par value (the “Class B Ordinary Shares”, and together with the Class A Ordinary Shares, the “Ordinary Shares”), and 1,000,000 preference shares, $0.0001 par value.

The following description summarizes the material terms of our capital stock and does not purport to be complete. It is subject to, and qualified in its entirety by reference to, our Amended and Restated Charter and the Warrant agreement, dated August 15, 2024, we entered into with Continental Stock Transfer & Trust Company, as warrant agent (the “Warrant Agreement”), each of which is incorporated by reference as an exhibit to our Annual Report on Form 10-K for the year ended December 31, 2024 (the “Report”) of which this Exhibit 4.5 is a part.

Defined terms used herein but not otherwise defined shall have the meaning ascribed to such terms in the Report.

Units

Each Unit consists of one Class A Ordinary Share and one-half of one redeemable Public Warrant. Pursuant to the Warrant Agreement, a warrant holder may exercise its Warrants only for a whole number of the Class A Ordinary Shares.

Class A Ordinary Shares

Ordinary shareholders of record are entitled to one vote for each share held on all matters to be voted on by shareholders. Holders of Class A Ordinary Shares and holders of Class B Ordinary Shares vote together as a single class on all matters submitted to a vote of our shareholders except as required by law. There is no cumulative voting with respect to the appointment of directors, with the result that the holders of more than 50% of the shares voted for the appointment of directors can elect all of the directors.

However, only holders of Class B Ordinary Shares have the right to appoint directors in any election held prior to the completion of our initial business combination, meaning that holders of Class A Ordinary Shares do not have the right to appoint any directors until after the completion of our initial business combination. In addition, only the Class B Ordinary Shares are entitled to vote to continue our Company in a jurisdiction outside of the Cayman Islands. Our shareholders are entitled to receive ratable dividends when, as and if declared by the Board of Directors out of funds legally available therefor.

We will provide our public shareholders with the opportunity to redeem all or a portion of their Public Shares upon the completion of our initial business combination at a per-share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account calculated as of two business days prior to the consummation of our initial business combination, including interest earned on the funds held in the Trust Account (which interest shall be net of permitted withdrawals), divided by the number of then outstanding Public Shares, subject to the limitations described herein. The per share amount we will distribute to public shareholders who properly redeem their Public Shares will not be reduced by the deferred underwriting commissions we will pay to the underwriters. Our Sponsor, officers and directors have entered into the Letter Agreement with us, pursuant to which they have agreed to waive their redemption rights with respect to any Founder Shares and Public Shares they hold in connection with the completion of our initial business combination.

If we seek shareholder approval of our initial Business Combination and we do not conduct redemptions in connection with our initial Business Combination pursuant to the tender offer rules, our Amended and Restated Charter provides 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 Exchange Act), will be restricted from redeeming its shares with respect to Excess Shares, without our prior consent. However, we would not be restricting our shareholders’ ability to vote all of their shares (including Excess Shares) for or against our initial Business Combination. Our shareholders’ inability to redeem the Excess Shares will reduce their influence over our ability to complete our initial Business Combination, and such shareholders could suffer a material loss in their investment if they sell such Excess Shares on the open market. Additionally, such shareholders will not receive redemption distributions with respect to the Excess Shares if we complete our initial Business Combination. And, as a result, such shareholders will continue to hold that number of shares exceeding 15% and, in order to dispose such shares would be required to sell their shares in open market transactions, potentially at a loss.

In the event of a liquidation, dissolution or winding up of the company after a Business Combination, our shareholders are entitled to share ratably in all assets remaining available for distribution to them after payment of liabilities and after provision is made for each class of shares, if any, having preference over the Ordinary Shares. Our shareholders have no preemptive or other subscription rights. There are no sinking fund provisions applicable to the Ordinary Shares, except that we will provide our Public Shareholders with the opportunity to redeem their Public Shares for cash at a per share price equal to the aggregate amount then on deposit in the Trust Account, including interest earned on the funds held in the Trust Account (which interest shall be net of permitted withdrawals), divided by the number of then outstanding Public Shares, upon the completion of our initial Business Combination, subject to the limitations described in the Report.

Redeemable Warrants

Each whole warrant entitles the registered holder to purchase one Class A Ordinary Share at a price of $11.50 per share, subject to adjustment as discussed below, at any time commencing 30 days after the completion of our initial business combination, provided that we have an effective registration statement under the Securities Act covering the Class A Ordinary Shares issuable upon exercise of the warrants and a current prospectus relating to them is available (or we permit holders to exercise their warrants on a cashless basis under the circumstances specified in the warrant agreement) and such shares are registered, qualified or exempt from registration under the securities, or blue sky, laws of the state of residence of the holder. Pursuant to the warrant agreement, a warrant holder may exercise its warrants only for a whole number of Class A Ordinary Shares. This means only a whole warrant may be exercised at a given time by a warrant holder. No fractional warrants will be issued upon separation of the units and only whole warrants will trade. Accordingly, unless you purchase at least two units, you will not be able to receive or trade a whole warrant.

The warrants will expire five years after the completion of our initial business combination, at 5:00 p.m., New York City time, or earlier upon redemption or liquidation. 

We will not be obligated to deliver any Class A Ordinary Shares pursuant to the exercise of a warrant and will have no obligation to settle such warrant exercise unless a registration statement under the Securities Act with respect to the Class A Ordinary Shares underlying the warrants is then effective and a prospectus relating thereto is current, subject to our satisfying our obligations described below with respect to registration. No warrant will be exercisable and we will not be obligated to issue a Class A ordinary share upon exercise of a warrant unless the Class A ordinary share issuable upon such warrant exercise has been registered, qualified or deemed to be exempt under the securities laws of the state of residence of the registered holder of the warrants. In the event that the conditions in the two immediately preceding sentences are not satisfied with respect to a warrant, the holder of such warrant will not be entitled to exercise such warrant and such warrant may have no value and expire worthless. In no event will we be required to net cash settle any warrant. In the event that a registration statement is not effective for the exercised warrants, the purchaser of a unit containing such warrant will have paid the full purchase price for the unit solely for the Class A ordinary share underlying such unit. 

We have agreed that, as soon as practicable, but in no event later than 20 business days, after the closing of our initial business combination, we will use our commercially reasonable efforts to file with the SEC a post-effective amendment to the IPO registration statement or a new registration statement covering the registration under the Securities Act of the Class A Ordinary Shares issuable upon exercise of the warrants and thereafter will use our commercially reasonable efforts to cause the same to become effective within 60 business days following our initial business combination and to maintain a current prospectus relating to the Class A Ordinary Shares issuable upon exercise of the warrants until the expiration of the warrants in accordance with the provisions of the warrant agreement. If a registration statement covering the Class A Ordinary Shares issuable upon exercise of the warrants is not effective by the sixtieth (60) business day after the closing of our initial business combination, warrant holders may, until such time as there is an effective registration statement and during any period when we will have failed to maintain an effective registration statement, exercise warrants on a “cashless basis” in accordance with Section 3(a)(9) of the Securities Act or another exemption. Notwithstanding the above, if our Class A Ordinary Shares are at the time of any exercise of a warrant not listed on a national securities exchange such that they satisfy the definition of a “covered security” under Section 18(b)(1) of the Securities Act, we may, at our option, require holders of Public Warrants who exercise their Warrants to do so on a “cashless basis” in accordance with Section 3(a)(9) of the Securities Act and, in the event we so elect, we will not be required to file or maintain in effect a registration statement.

2

Redemption of Warrants when the price per Class A ordinary share equals or exceeds $18.00. Once the Warrants become exercisable, we may redeem the outstanding Warrants:

● in whole and not in part;

● at a price of $0.01 per Warrant upon a minimum of 30 days’ prior written notice of redemption (the “30-day redemption period”); and

● if, and only if, the closing price of the Class A Ordinary Shares equals or exceeds $18.00 per share (as adjusted for adjustments to the number of shares issuable upon exercise or the exercise price of a Warrant as described under the heading “-Redemption Procedures-Anti-dilution Adjustments”) for any 20 trading days within a 30-trading day period commencing at least 30 days after completion of our initial business combination and ending three business days before we send the notice of redemption to the Warrant holders.

We will not redeem the Warrants as described above unless a registration statement under the Securities Act covering the issuance of the Class A Ordinary Shares issuable upon exercise of the Warrants is then effective and a current prospectus relating to those Class A Ordinary Shares is available throughout the measurement period. If and when the Warrants become redeemable by us, we may not exercise our redemption right if the issuance of Ordinary Shares upon exercise of the Warrants is not exempt from registration or qualification under applicable state blue sky laws or we are unable to effect such registration or qualification. We will use our best efforts to register or qualify such Ordinary Shares under the blue sky laws of the state of residence in those states in which the Warrants were offered by us in this offering. We have established the last of the redemption criterion discussed above to prevent a redemption call unless there is at the time of the call a significant premium to the Warrant exercise price. If the foregoing conditions are satisfied and we issue a notice of redemption of the Warrants, each Warrant holder will be entitled to exercise his, her or its Warrant prior to the scheduled redemption date. However, the price of the Class A Ordinary Shares may fall below the $18.00 redemption trigger price (as adjusted for share sub-divisions, share capitalizations, reorganizations, recapitalizations and the like) as well as the $11.50 Warrant exercise price after the redemption notice is issued.

Redemption procedures.

A holder of a Warrant may notify us in writing in the event it elects to be subject to a requirement that such holder will not have the right to exercise such Warrant, to the extent that after giving effect to such exercise, such person (together with such person’s affiliates), to the Warrant agent’s actual knowledge, would beneficially own in excess of 4.9% or 9.8% (as specified by the holder) of the Class A Ordinary Shares outstanding immediately after giving effect to such exercise.

The Warrants have certain anti-dilution and adjustments rights upon certain events.

The Warrants were issued in registered form under the Warrant Agreement. The Warrants may be amended without the consent of any holder to cure any ambiguity or correct any defective provision, and that all other modifications or amendments will require the vote or written consent of the holders of at least 50% of the then outstanding Warrants.

The Warrants may be exercised upon surrender of the Warrant certificate on or prior to the expiration date at the offices of the Warrant agent, with the exercise form on the reverse side of the Warrant certificate completed and executed as indicated, accompanied by full payment of the exercise price (or on a cashless basis, if applicable), by certified or official bank check payable to us, for the number of Warrants being exercised. The Warrant holders do not have the rights or privileges of holders of Ordinary Shares and any voting rights until they exercise their Warrants and receive Class A Ordinary Shares. After the issuance of Class A Ordinary Shares upon exercise of the Warrants, each holder will be entitled to one vote for each share held of record on all matters to be voted on by shareholders. 

No fractional shares will be issued upon exercise of the Warrants. If, upon exercise of the Warrants, a holder would be entitled to receive a fractional interest in a share, we will, upon exercise, round down to the nearest whole number the number of Class A Ordinary Shares to be issued to the Warrant holder.

3