Exhibit 4.3


 


Schedule of Holders


of


Warrants to Purchase
Series A1 Preferred Stock


Of Rapid Micro Biosystems, Inc.


 


	Holder	 	Number

 of Shares	 	 	Issuance Date	 	Expiration

 Date
	Foster & Foster Capital V LLC	 	 	39,266	 	 	July 24, 2017	 	July 24, 2027
	Longitude Venture Partners II, L.P.	 	 	2,500,000	 	 	July 24, 2017	 	July 24, 2027
	Mellon Family Investment Company V	 	 	273,227	 	 	July 24, 2017	 	July 24, 2027
	Quaker Bioventures II, L.P.	 	 	410,051	 	 	July 24, 2017	 	July 24, 2027
	Richard King Mellon Foundation	 	 	273,227	 	 	July 24, 2017	 	July 24, 2027
	TVM Life Science Ventures VI GmbH & Co. K.G.	 	 	244,093	 	 	July 24, 2017	 	July 24, 2027
	TVM Life Science Ventures VI, L.P.	 	 	83,660	 	 	July 24, 2017	 	July 24, 2027






 






     


     


    

 


THIS WARRANT AND THE SECURITIES ISSUABLE
UPON THE EXERCISE HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THEY MAY NOT BE SOLD, OFFERED
FOR SALE, PLEDGED, HYPOTHECATED, OR OTHERWISE TRANSFERRED EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT REGISTRATION IS NOT REQUIRED UNDER SUCH ACT
OR UNLESS SOLD PURSUANT TO RULE 144 UNDER SUCH ACT.


 


	Date of Issuance:

 July 24,
    2017	 	Void after
    July 24, 2027, unless

 earlier terminated pursuant to the

 terms hereof 


 


RAPID MICRO BIOSYSTEMS, INC.

WARRANT TO PURCHASE SHARES OF SERIES A1 PREFERRED STOCK


 


This Warrant (this
 “Warrant”) is issued to [                          ] or his, her or its assigns (the “Holder”) by Rapid Micro Biosystems, Inc.,
a Delaware corporation (the “Company”), pursuant to that certain Series A1 Preferred Stock Purchase Agreement
dated as of July 24, 2017 among the Company, the Holder and certain other investors, as the same may be amended, restated
or otherwise modified from time to time (the “Purchase Agreement” and all warrants issued under the Purchase
Agreement collectively, the “Warrants”).


 


Unless otherwise defined
herein or in the Purchase Agreement, capitalized terms shall have the following meanings:


 


“Corporate
Transaction” shall mean (A) the closing of the sale, transfer or other disposition of all or substantially all
of the Company’s assets, (B) the consummation of the merger or consolidation of the Company with or into another entity
(except a merger or consolidation in which the holders of capital stock of the Company immediately prior to such merger or consolidation
continue to hold at least 50% of the voting power of the capital stock of the Company or the surviving or acquiring entity), or
(C) the closing of the transfer (whether by merger, consolidation or otherwise), in one transaction or a series of related
transactions, to a person or group of affiliated persons (other than an underwriter of this corporation’s securities), of
the Company’s securities if, after such closing, such person or group of affiliated persons would hold 50% or more of the
outstanding voting stock of this corporation (or the surviving or acquiring entity); provided, however, that a transaction
shall not constitute a Corporate Transaction if its sole purpose is to change the state of the Company’s incorporation or
to create a holding company that will be owned in substantially the same proportions by the persons who held the Company’s
securities immediately prior to such transaction. Notwithstanding the prior sentence, the sale of shares of Preferred Stock in
a bona fide financing transaction shall not be deemed a Corporate Transaction.


 


“Exercise Price”
shall mean $0.01 per Share.


 






     


     


    

 


“Original Date
of Issuance” shall mean July 24, 2017.


 


“Preferred
Stock” shall mean the Company’s Series A1 Preferred Stock, $0.01 par value per share.


 


“Shares”
shall mean shares of Preferred Stock.


 


1.            Purchase
of Shares; Number of Shares and Exercise Price. Subject to the terms and conditions set forth herein, the Holder is entitled,
upon surrender of this Warrant at the principal office of the Company (or at such other place as the Company shall notify the
Holder in writing), to purchase from the Company up to [                    ] fully paid and nonassessable Shares. The Shares and the Exercise Price
of the Shares shall be subject to adjustment pursuant to Section 6 hereof.


 


2.            Exercise
Period; Termination. Unless earlier terminated pursuant to the terms hereof, this Warrant shall be exercisable, in whole or
in part, during the period commencing on the Original Date of Issuance and ending at 5:00 p.m. pacific time on July 24,
2027 (the “Exercise Period”). In the event that this Warrant has not been otherwise terminated pursuant to
this Section 2, upon the expiration of the Exercise Period, if the fair market value of one Conversion Share (or other security
issuable upon the exercise hereof) as determined in accordance with Section 4 below is greater than the Exercise Price in
effect on such date, then this Warrant, to the extent then exercisable, shall automatically be deemed on and as of such date to
be exercised pursuant to Section 4 below as to all Shares (or such other securities) for which it shall not have been previously
exercised, and the Company shall, within a reasonable time, deliver a certificate representing the Shares (or such other securities)
issued upon such exercise to Holder.


 


3.            Method
of Exercise.


 


(a)          While
this Warrant remains outstanding and exercisable in accordance with Section 2 above, the Holder may exercise, in whole or
in part, the purchase rights evidenced hereby. Such exercise shall be effected by:


 


(i)          the
surrender of the Warrant, together with a duly executed copy of the Notice of Exercise attached hereto, to the Secretary of the
Company at its principal office (or at such other place as the Company shall notify the Holder in writing); and


 


(ii)          the
payment to the Company of an amount equal to the aggregate Exercise Price for the number of Shares being purchased.


 


(b)          Each
exercise of this Warrant shall be deemed to have been effected immediately prior to the close of business on the day on which
this Warrant is surrendered to the Company as provided in Section 3(a) above. At such time, the person or persons in
whose name or names any certificate for the Shares shall be issuable upon such exercise as provided in Section 3(c) below
shall be deemed to have become the holder or holders of record of the Shares represented by such certificate.


 






     


     


    

 


(c)          As
soon as practicable after the exercise of this Warrant in whole or in part, and in any event within twenty (20) days thereafter,
the Company at its expense will cause to be issued in the name of, and delivered to, the Holder, or as such Holder (upon payment
by such Holder of any applicable transfer taxes) may direct:


 


(i)          a
certificate or certificates for the number of Shares to which such Holder shall be entitled, and


 


(ii)          in
case such exercise is in part only, a new warrant or warrants (dated the date hereof) of like tenor, calling in the aggregate
on the face or faces thereof for the number of Shares equal to the number of such Shares called for on the face of this Warrant
minus the number of Shares purchased by the Holder upon all exercises made in accordance with Section 3(a) above or
Section 4 below.


 


4.            Net
Exercise. In lieu of exercising this Warrant for cash, the Holder may elect to receive shares equal to the value of this Warrant
(or the portion thereof being exercised) by surrender of this Warrant at the principal office of the Company together with notice
of such election (a “Net Exercise”). A Holder who Net Exercises shall have the rights described in Sections
3(b) and 3(c) hereof, and the Company shall issue to such Holder a number of Shares computed using the following formula:


 


 


 


 Where




 


		X =	The number of Shares to be issued to
                                         the Holder.



 


		Y =	The number of Shares purchasable under
                                         this Warrant or, if only a portion of the Warrant is being exercised, the portion of
                                         the Warrant being cancelled (at the date of such calculation).



 


		A =	The fair market value of one (1) Conversion
                                         Share (at the date of such calculation).



 


		B =	The Exercise Price (as adjusted to
                                         the date of such calculations).



 


For purposes of this
Section 4, the fair market value of a Conversion Share shall mean the average of the closing price of the Shares (or equivalent
shares of Common Stock underlying the Shares) quoted in the over-the-counter market in which the Shares (or equivalent shares
of Common Stock underlying the Shares) are traded or the closing price quoted on any exchange or electronic securities market
on which the Shares (or equivalent shares of Common Stock underlying the Warrant) are listed, whichever is applicable, as published
in The Wall Street Journal for the five (5) trading days prior to the date of determination of fair market value
(or such shorter period of time during which such Shares were traded over-the-counter or on such exchange). In the event that
this Warrant is exercised pursuant to this Section 4 in connection with the Company’s first underwritten public offering
pursuant to an effective registration statement under the Securities Act of 1933, as amended (the “IPO”), the
fair market value per Conversion Share shall be the product of (a) the per share offering price to the public of the IPO,
and (b) the number of shares of Common Stock into which each Conversion Share is convertible at the time of such exercise
or, if the Shares are shares of Common Stock, one. In the event that this Warrant is exercised not in connection with the IPO
and the Shares are not traded on the over-the-counter market, an exchange or an electronic securities market, the fair market
value shall be the price per Conversion Share that the Company could obtain from a willing buyer for Shares sold by the Company
from authorized but unissued Shares, as such prices shall be determined in reasonable good faith by the Company’s Board
of Directors.


 






     


     


    

 


5.            Covenants
of the Company.


 


(a)          Notices
of Record Date. In the event of any taking by the Company of a record of the holders of any class of securities for the purpose
of determining the holders thereof who are entitled to receive any dividend (other than a cash dividend which is the same as cash
dividends paid in previous quarters or a stock dividend) or other distribution, the Company shall mail to the Holder, at least
ten (10) days prior to such record date, a notice specifying the date on which any such record is to be taken for the purpose
of such dividend or distribution.


 


(b)          Covenants
as to Exercise Shares. The Company covenants and agrees that all Shares that may be issued upon the exercise of the rights
represented by this Warrant will, upon issuance in accordance with the terms hereof, be validly issued and outstanding, fully
paid and nonassessable, and free from all taxes, liens and charges with respect to the issuance thereof. The Company further covenants
and agrees that the Company will at all times during the Exercise Period have authorized and reserved, free from preemptive rights,
a sufficient number of shares of its Preferred Stock to provide for the exercise of the rights represented by this Warrant. If
at any time during the Exercise Period the number of authorized but unissued shares of Preferred Stock shall not be sufficient
to permit exercise of this Warrant, the Company will take such corporate action as may, in the opinion of its counsel, be necessary
to increase its authorized but unissued shares of Preferred Stock to such number of shares as shall be sufficient for such purposes.


 


6.            Adjustment
of Exercise Price and Number of Shares. The number and kind of Shares purchasable upon exercise of this Warrant and the Exercise
Price shall be subject to adjustment from time to time as follows:


 


(a)          Subdivisions,
Combinations and Other Issuances. If the Company shall at any time after the issuance but prior to the expiration of this
Warrant subdivide its Preferred Stock, by split-up or otherwise, or combine its Preferred Stock, or issue additional shares of
its Preferred Stock or Common Stock as a dividend with respect to any shares of its Preferred Stock, the number of Shares issuable
on the exercise of this Warrant shall forthwith be proportionately increased in the case of a subdivision or stock dividend, or
proportionately decreased in the case of a combination. Appropriate adjustments shall also be made to the Exercise Price payable
per share, but the aggregate Exercise Price payable for the total number of Shares purchasable under this Warrant (as adjusted)
shall remain the same. Any adjustment under this Section 6(a) shall become effective at the close of business on the
date the subdivision or combination becomes effective, or as of the record date of such dividend, or in the event that no record
date is fixed, upon the making of such dividend.


 






     


     


    

 


(b)          Reclassification,
Reorganization and Consolidation. In case of any reclassification, capital reorganization or change in the capital stock of
the Company (other than as a result of a subdivision, combination or stock dividend provided for in Section 6(a) above),
then, as a condition of such reclassification, reorganization or change, lawful provision shall be made, and duly executed documents
evidencing the same from the Company or its successor shall be delivered to the Holder, so that the Holder shall have the right
at any time prior to the expiration of this Warrant to purchase, at a total price equal to that payable upon the exercise of this
Warrant, the kind and amount of shares of stock and other securities or property receivable in connection with such reclassification,
reorganization or change by a holder of the same number and type of securities as were purchasable as Shares by the Holder immediately
prior to such reclassification, reorganization or change. In any such case appropriate provisions shall be made with respect to
the rights and interest of the Holder so that the provisions hereof shall thereafter be applicable with respect to any shares
of stock or other securities or property deliverable upon exercise hereof, and appropriate adjustments shall be made to the Exercise
Price per Conversion Share payable hereunder, provided the aggregate Exercise Price shall remain the same.


 


(c)          Corporate
Transaction. In the event of a Corporate Transaction, pursuant to which the Holder would have been entitled to receive cash
consideration per Conversion Share in an amount greater than the Exercise Price if the Holder had exercised his, her or its rights
pursuant to this Warrant immediately prior thereto, the Company shall pay to the Holder, at the closing of such transaction, an
amount equal to (i) the number of Shares issuable hereunder, multiplied by (ii) the difference of (A) the cash
consideration per Conversion Share that the Holder would have received if he, she or it had exercised his, her or its rights pursuant
to this Warrant immediately prior to the closing of such transaction, minus (B) the Exercise Price. This Warrant, and all
rights of the Holder hereunder, shall automatically be terminated immediately upon delivery of such payment. If the Holder would
have been entitled to receive cash consideration per Share in an amount equal to or less than the Exercise Price if the Holder
had exercised his, her or its rights pursuant to this Warrant immediately prior to any such transaction, then this Warrant, and
all rights of the Holder hereunder, shall automatically be terminated upon the closing of any such transaction.


 


(d)          Adjustments
for Diluting Issuances. Without duplication of any adjustment otherwise provided for in this Section 6, the number of
shares of common stock issuable upon conversion of the Shares shall be subject to anti-dilution adjustment from time to time in
the manner set forth in the Company’s Certificate of Incorporation as if the Shares were issued and outstanding on and as
of the date of any such required adjustment.


 


(e)          Notice
of Adjustment. When any adjustment is required to be made in the number or kind of shares purchasable upon exercise of the
Warrant, or in the Exercise Price, the Company shall promptly notify the Holder of such event and of the number of Shares or other
securities or property thereafter purchasable upon exercise of this Warrant.


 


(f)          Conversion
of Preferred Stock. In the event that all outstanding shares of Preferred Stock are converted to Common Stock, or any other
security, in accordance with the terms of the Restated Certificate in connection with the IPO, a Corporate Transaction or other
event, this Warrant shall become exercisable for Common Stock or such other security.


 






     


     


    

 


7.            No
Fractional Shares or Scrip. No fractional shares or scrip representing fractional shares shall be issued upon the exercise
of this Warrant, but in lieu of such fractional shares the Company shall make a cash payment therefor on the basis of the Exercise
Price then in effect.


 


8.            No
Stockholder Rights. Other than in respect of the adjustments provided in Section 6 hereof, prior to exercise of this
Warrant, the Holder shall not be entitled to any rights of a stockholder with respect to the Shares, including (without limitation)
the right to vote such Shares, receive dividends or other distributions thereon, exercise preemptive rights or be notified of
stockholder meetings, and except as otherwise provided in this Warrant or the Purchase Agreement, such Holder shall not be entitled
to any stockholder notice or other communication concerning the business or affairs of the Company.


 


9.            Notice
of Certain Events. If the Company proposes at any time to:


 


(a)          declare
any dividend or distribution upon the outstanding shares of the Company’s capital stock, whether in cash, property, stock,
or other securities and whether or not a regular cash dividend;


 


(b)          effect
any reclassification, exchange, combination, substitution, reorganization or recapitalization of the outstanding shares of the
Company’s capital stock;


 


(c)          effect
a Corporate Transaction or to liquidate, dissolve or wind up; or


 


(d)          effect
the IPO;


 


then, in connection with each such event, the Company shall
give Holder:


 


(i)          at
least seven (7) business days prior written notice of the date on which a record will be taken for such dividend, distribution,
or subscription rights (and specifying the date on which the holders of outstanding shares of the Company’s capital stock
will be entitled thereto) or for determining rights to vote, if any, in respect of the matters referred to in (a) above;


 


(ii)         in
the case of the matters referred to in (b) and (c) above at least seven (7) business days prior written
notice of the date when the same will take place (and specifying the date on which the holders of outstanding shares of the Company’s
capital stock will be entitled to exchange their shares for the securities or other property deliverable upon the occurrence of
such event and such reasonable information as Holder may reasonably require regarding the treatment of this Warrant in connection
with such event giving rise to the notice); and


 


(iii)        with
respect to the IPO, at least seven (7) business days prior written notice of the date on which the Company proposes to file
its registration statement in connection therewith.


 


The Company will also provide information requested by Holder
that is reasonably necessary to enable Holder to comply with Holder’s accounting or reporting requirements.


 






     


     


    

 


10.            Transfer
of Warrant. Subject to compliance with applicable federal and state securities laws, this Warrant and all rights hereunder
are transferable in whole or in part by the Holder to any person or entity upon written notice to the Company. Within a reasonable
time after the Company’s receipt of an executed Assignment Form in the form attached hereto, the transfer shall be
recorded on the books of the Company upon the surrender of this Warrant, properly endorsed, to the Company at its principal offices,
and the payment to the Company of all transfer taxes and other governmental charges imposed on such transfer. In the event of
a partial transfer, the Company shall issue to the new holders one or more appropriate new warrants.


 


11.            Successors
and Assigns. The terms and provisions of this Warrant shall inure to the benefit of, and be binding upon, the Company and
the holders hereof and their respective successors and assigns.


 


12.            Titles
and Subtitles. The titles and subtitles used in this Warrant are used for convenience only and are not to be considered in
construing or interpreting this Warrant.


 


13.            Amendments
and Waivers. Any term of this Warrant may be amended and the observance of any term of this Warrant may be waived (either
generally or in a particular instance and either retroactively or prospectively), with the written consent of the Company and
the holders of Warrants holding a majority of the Shares issuable upon exercise of the Warrants issued pursuant to the Purchase
Agreement; provided that such amendment affects each such holder in materially the same manner. Any waiver or amendment effected
in accordance with this Section 13 shall be binding upon each holder of a Warrant at the time outstanding and each future
holder of all such Warrants.


 


14.            Governing
Law. This Warrant and any controversy arising out of or relating to this Warrant shall be governed by, and construed in accordance
with, the internal laws of the State of Delaware.


 


15.            Notices.
All notices and other communications given or made pursuant hereto shall be in writing and shall be deemed effectively given:
(a) upon personal delivery to the party to be notified, (b) when sent by confirmed electronic mail or facsimile if sent
during normal business hours of the recipient, and if not so confirmed, then on the next business day, (c) five (5) days
after having been sent by registered or certified mail, return receipt requested, postage prepaid, or (d) one (1) day
after deposit with a nationally recognized overnight courier, specifying next day delivery, with written verification of receipt.
All communications shall be sent to the respective parties at the following addresses (or at such other addresses as shall be
specified by notice given in accordance with this Section 15):


 


If to the Company:


 


RAPID MICRO BIOSYSTEMS, INC.


1001 Pawtucket Blvd.


Lowell, MA 01854


Attention: Chief Executive Officer


 






     


     


    

 


If to Holders:


 


At the addresses shown on the
signature pages hereto.


 


16.            Severability.
If any provision of this Warrant is held to be unenforceable under applicable law, such provision shall be excluded from this
Warrant and the balance of the Warrant shall be interpreted as if such provision were so excluded and shall be enforceable in
accordance with its terms.


 


[Remainder
of Page Intentionally Left Blank]


 






     


     


    

 


IN WITNESS WHEREOF,
the parties have executed this Warrant as of the date first written above.


 


	 	RAPID MICRO BIOSYSTEMS, INC.
	 	 
	 	By:	 /s/ Robert Spignesi
	 	Name:	Robert Spignesi
	 	Title:	President and Chief Executive Officer



 






     


     


    

 


IN WITNESS WHEREOF,
the parties have executed this Warrant as of the date first written above.


 


	 	[ l ]
	 	 
	 	 
	 	By:	 
	 	Name:	 
	 	Title:	 
	 	 
	 	 
	 	Address: 
	 	 
	 	 
	 	 
	 	 



 






     


     


    

 


NOTICE OF EXERCISE


 


RAPID MICRO BIOSYSTEMS, INC.


 


Attention: Corporate Secretary


 


The undersigned hereby
elects to purchase, pursuant to the provisions of the Warrant, as follows:


 


		 ̈	_____________
                                         Shares pursuant to the terms of the attached Warrant, and tenders herewith payment in
                                         cash of the Exercise Price of such Shares in full, together with all applicable transfer
                                         taxes, if any.



 


		 ̈	Net
                                         Exercise the attached Warrant with respect to __________ Shares.



 


The undersigned hereby
represents and warrants that Representations and Warranties of the undersigned in Section 3 of the Purchase Agreement are
true and correct as of the date hereof.


 


	 	 	 	 	HOLDER:
	 	 	 	 	 
	 	 	 	 	 
	Date:	 	 	 	By: 	 
	 	 	 	 	 
	 	 	 	 	 
	 	 	 	Address:	 
	 	 	 	 	 
	 	 	 	 	 
	 	 	 	 	 
	Name in which shares should be registered:	 	 	 
	 	 	 	 
	 	 	 	 



 






     


     


    

 


ASSIGNMENT
FORM


 


(To assign the foregoing Warrant, execute


this form
and supply required information.


Do not use this form to purchase shares.)


 


For
Value Received, the foregoing Warrant and all rights evidenced thereby are hereby assigned to


 


 


	Name:	 
	 	(Please Print)



 


 


	Address:	 
	 	(Please Print)



 


	Dated: 	 	 



 


 


	Holder’s
	Signature:	 	 



 


 


	Holder’s
	Address:	 	 



 


 


NOTE: The signature to this Assignment
Form must correspond with the name as it appears on the face of the Warrant. Officers of corporations and those acting in
a fiduciary or other representative capacity should provide proper evidence of authority to assign the foregoing Warrant.


 






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