Document:

EX-10.5

 Exhibit 10.5 
  

			
	

	  	 215 First Street, Suite 400-S

Cambridge, MA 02142
 617.949.4360

omegatherapeutics.com

 March 2, 2019 
 Mahesh
Karande 
 [XXX] 
 [XXX] 

Dear Mahesh, 
 On behalf of Omega Therapeutics (the
“Company”), a Flagship Pioneering Company, I am delighted to make this conditional offer of employment with the Company. This offer letter (the “Offer Letter”) and the accompanying documents and agreements summarize and set forth
important terms about your employment with the Company. 
 1. Starting Date, Position, and Duties. 

a. Your position with the Company shall be President and Chief Executive Officer and, subject to applicable corporate and procedural
requirements, you also shall be elected to serve as a member of the Company’s Board of Directors (the “Board”). In your role as Chief Executive Officer, you shall report to the Board. Provided that the above-stated work authorization
conditions are met, we anticipate that your employment shall start effective April 8, 2018 or such earlier date as mutually agreed (the “Start Date”). In this key position you shall have responsibility for driving the strategic
direction of the Company, as well as oversight of all operational activities of the Company. In your role you are expected to build and supervise a team to execute against objectives and to develop and manage processes and systems to support these
functions. You shall also be expected to perform such other services for the Company consistent with your position as Chief Executive Officer, as may be assigned to you from time to time by the Board or its authorized committee. As a member of our
team, we expect you to devote all of your professional and working time and energies to the business and affairs of the Company. As a member of the Flagship Pioneering ecosystem, it is expected that the Board of Directors that you may join will be
from within the Flagship Pioneering ecosystem. As such, it is understood that you may be asked to join the Board of Directors of one or more Flagship Pioneering companies and will be compensated as agreed between you and such other Boards of
Directors. 
 b. As is generally true for Company employees, you shall be employed on an
at-will basis, which means that neither you nor the Company are guaranteeing this employment relationship for any specific period of time. Either of us may choose to end the employment

 
relationship at any time, for any reason, with or without notice. If any benefit is subject to a benefit plan, the terms of that plan shall control. Other than the terms of this Offer Letter, the
Company reserves the right to alter, supplement or rescind its employment procedures, benefits or policies (other than the employment at-will policy) at any time in its sole and absolute discretion and without
notice. 
 c. As stated above, you shall serve as a member of the Board during your employment hereunder. You acknowledge and agree
that you shall resign from the Board effective immediately upon the termination of your employment with the Company for any reason. 
 2. Compensation.

 a. Salary. Your initial base pay shall be at a rate of $472,000.00 on an annualized basis, minus customary deductions
for federal and state taxes and the like, and in accordance with the Company’s normal payroll practices. Your annual base salary shall be reviewed for appropriate increases in accordance with the Company’s policy, but shall not be
decreased except in the case of an across-the-board reduction that is implemented for all similarly situated executives of the Company. 

b. Annual Performance Bonus. You shall be eligible to receive an annual bonus, with a target bonus opportunity of 50% of your
base salary, payable upon the achievement, as determined by the Board in its sole discretion, of specific milestones to be mutually agreed with you in writing. The annual bonus shall be paid to you no later than March 15th of the calendar year
immediately following the calendar year in which it was earned. You must be employed by the Company on the last day of the calendar year to which a bonus relates in order to be eligible for and have earned the annual bonus. 

c. Equity Grants. Subject to the terms and conditions of this Section 2.c. and any applicable policies and agreements
(including but not limited to the “Equity Plan” and “Equity Agreements” described below), you shall be eligible for the following option grant: 
  

	 	i.	 Option Grant. On the Start Date, the Board shall grant you a stock option to purchase 3,784,514 shares
of common stock of the Company (the “Sign-On Grant”), which is intended to equal approximately 6.0% of the fully diluted shares of Company stock at the completion of the final tranche of the Series A
preferred stock financing (the “Series A Financing”), at a price per share equal to the fair market value of the common stock on the date of grant as determined by the Board. As such, you shall receive, if needed, an additional stock
option grant following your Start Date so that at the completion of the final tranche of the Series A financing you shall have stock options equal to 6.0% of the fully diluted shares of Company stock. 25% of the stock option shall

  
 2 

	 	
vest on the 1st anniversary of your Start Date, and the remaining 75% of the stock option shall vest quarterly over the 3-year period following such
anniversary, subject to your continued employment with the Company. After completion of the Series A Financing you shall be eligible for additional stock option grants as determined by the Board. 

 

	 	ii.	 Terms and Conditions. In all respects, the stock options described in this Section 2 shall be
governed by the 2017 Equity Incentive Plan (the “Equity Plan”) (or any successor or additional plan thereto which such stock option is granted) and a stock option agreement in the form of the Company’s standard form of stock option
agreement under the Equity Plan (as applicable, an “Equity Agreement”) executed by you pursuant thereto, copies of which have been provided to you. The stock options described in this Section 2 shall be, to the maximum extent
permissible, treated as “incentive stock options” within the meaning of Section 422 of the Internal Revenue Code and the rules and regulations thereunder. 

 

	 	iii.	 Accelerated Vesting. If you are subject to an Involuntary Termination (as defined below) outside of a
CIC Period (as defined below), then subject to your execution of a Separation Agreement (as defined below) that becomes effective and irrevocable within 60 days following your Separation (as defined below), the vesting and, if applicable, the
exercisability of each of your outstanding equity-based awards under the Equity Plan or any additional equity-based plan maintained by the Company or any applicable successor plans thereto, including but not limited to the Sign-On Grant, shall be partially accelerated such that the number of shares subject to each such equity-based award that would have vested during the 12 month period following your Separation (or, in the case of an
equity-based award in which vesting of the shares is subject to the achievement of a performance-based condition, then 25% of the shares subject to such equity-based award) shall be vested and, if applicable, exercisable as of the date of your
Separation. In addition, if you are subject to an Involuntary Termination during the CIC Period, then subject to your execution of a Separation Agreement that becomes effective and irrevocable within 60 days following your Separation, all of your
then-unvested equity-based awards under the Equity Plan or any additional equity-based plan maintained by the Company or any applicable successor plans thereto, including but not limited to the Sign-On Grant,
shall be fully accelerated and, if applicable, exercisable as of the date of your Separation. 

  
 3 

 d. Benefits. You shall be eligible to participate in the Company’s
benefit plans to the same extent as, and subject to the same terms, conditions and limitations applicable to, other Company executives. Summaries of each of the Company’s benefit plans are available to you. These benefits may be modified,
changed or eliminated from time to time at the sole discretion of the Company, and the provision of such benefits does not change your status as an at-will employee. Where a particular benefit is subject to a
formal plan (for example, medical insurance or life insurance), eligibility to participate in and receive any particular benefit is governed solely by the applicable plan document. Each calendar year you shall be eligible to accrue four
(4) weeks’ vacation and holidays as set forth by the Company and subject to the Company’s vacation and holiday policies as in effect from time to time. 

e. Travel and Lodging Allowance. The Company shall provide you with an allowance of $5,000 per month for reasonable lodging
expenses in the Cambridge, MA vicinity. The Company shall also cover reasonable travel expenses related to your commute between your home location and the Company’s office location in Cambridge, MA, provided that air travel shall be by coach
and train travel may be by business class. The actual out-of-pocket spend will be grossed up at the appropriate tax rate. 

f. Expense Reimbursement. The Company shall reimburse you for all ordinary and reasonable out-of-pocket business expenses incurred in furtherance of the Company’s business in accordance with the Company’s policies with respect thereto as in effect from time to time. You must submit any
request for reimbursement no later than ninety (90) days following the date that such business expense is incurred. All reimbursements hereunder shall be made or provided in accordance with the requirements of Section 409A
(“Section 409A”) of the Internal Revenue Code and the rules and regulations thereunder (the “Code”) including, where applicable, the requirement that: (i) any reimbursement is for expenses incurred during your lifetime
(or during a shorter period of time specified in this Offer Letter); (ii) the amount of expenses eligible for reimbursement during a calendar year may not affect the expenses eligible for reimbursement in any other calendar year; (iii) the
reimbursement of an eligible expense shall be made no later than the last day of the calendar year following the year in which the expense is incurred; and (iv) the right to reimbursement or in kind benefits is not subject to liquidation or
exchange for another benefit. 
 3. Severance Benefit upon Involuntary Termination. 

a. Notwithstanding the at-will nature of the parties’ relationship, should you be subject
to an Involuntary Termination, then conditioned upon your execution of a separation agreement substantially in the form attached hereto as Exhibit A (the “Separation Agreement”) that becomes effective and irrevocable within 60 days
following your Separation and compliance with your Confidentiality Agreement described below then: (i) the Company shall provide you with continued payment your then current base salary (but prior to taking into account any reduction that
triggers Good Reason) for a period of 9 months (or 12 months in the event such Involuntary Termination occurs following the first closing of 

  
 4 

 
the Company’s Series B preferred stock financing (the “Series B Financing”)), payable in one-time
lump-sum payment within 60 days following your Separation; less applicable withholdings, subject to Section 3(i); (ii) any earned, but unpaid annual bonus for the calendar year prior to the calendar year
in which your Involuntary Termination occurs; (iii) (x) if the Company is subject to the Consolidated Omnibus Budget Reconciliation Act (“COBRA”) or similar state law, (y) the premium subsidy described below is not illegal or
discriminatory under the Code, the Patient Protection and Affordable Care Act or the Health Care and Education Reconciliation Act, and (z) if you properly elect to receive benefits under COBRA, then the Company shall provide you, for a period
of 9 months (or 12 months in the event such Involuntary Termination occurs following the first closing of the Series B Financing) following your Separation, your COBRA premiums at the Company’s normal rate of contribution for employees for your
coverage at the level in effect immediately prior to your termination, provided that if the subsidy is limited by clause (y) then you shall receive a monthly cash payment equal to the monthly COBRA premium that you are required to pay for such
COBRA coverage; and (iv) subject to the terms and conditions of the Equity Plan (or any successor or additional plan thereto) and Equity Agreements, any portion of an option that has vested or has had the time-based requirement satisfied shall
remain outstanding for a period of 12 months following the Separation date or, if earlier, the normal 10-year expiration date of such stock options. In addition, you shall receive all (w) accrued, but
unpaid, base salary earned by, but not paid to you, prior to your date of Separation, which will be paid to you on the next payroll date following your date of Separation, x) any incentive bonus that was earned for the prior calendar year but not
paid, which will be paid to you at the same time that bonuses are paid to other executives, (y) any amounts accrued and due under the terms of any employee benefit plan in which you participated while employed (e.g., 401(k)), which will be paid
to you at the time provided under the applicable plan and (z) any amounts owing to you under Section 2(f) for reimbursement of expenses incurred by you prior to your date of Separation, which will be paid to you in accordance with the
Company’s policies with respect thereto (collectively, the “Accrued Benefits”). 
 b. For purposes of this Offer
Letter, “Cause” means any one or more of the following actions: (i) your material breach of the terms of this Offer Letter or your Employee Non-Competition,
Non-Solicitation, Confidentiality and Assignment Agreement; (ii) your material dishonesty, willful misconduct, gross negligence, or reckless conduct, in each case, if such conduct is in connection with
the performance of your services to the Company; (iii) your commission of an act of fraud, theft, misappropriation or embezzlement that is, in each case, materially injurious to the Company; (iv) your conviction of, or pleading nolo
contendere to, any crime involving moral turpitude felony (other than traffic offenses); or (v) your material violation of a Company policy that had been previously provided to you in writing your willful refusal to to substantially perform
your assigned duties to the Company (other than as a result of your mental or physical impairment), provided that such policy compliance or performance of duties would not cause you to violate law. For purpose of clauses (i), (ii), (iii), and (v),
“Cause” shall only exist if: (1) the Company delivered to you a 

  
 5 

 
written description of the events or conditions giving rise to your termination for Cause; and (2) if curable, you have been given at least 30 days to cure such events or conditions and you
fail to cure such events or conditions within such time period given. 
 c. For purposes of this Offer Letter, “Change of
Control” means: (i) any “Person” (as such term is used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) becomes the “Beneficial Owner” (as defined in
Rule 13d-3 under the Exchange Act), directly or indirectly, of securities of the Company representing 50% or more of the total voting power represented by the Company’s then outstanding voting securities
(excluding for this purpose any such voting securities held by the Company or its affiliates or by any employee benefit plan of the Company) pursuant to a transaction or a series of related transactions which the Board does not approve; or
(ii) a merger or consolidation of the Company whether or not approved by the Board, other than a merger or consolidation which would result in the voting securities of the Company outstanding immediately prior thereto continuing to represent
(either by remaining outstanding or by being converted into voting securities of the surviving entity or the parent of such corporation) more than 50% of the total voting power represented by the voting securities of the Company or such surviving
entity or parent of such corporation, as the case may be, outstanding immediately after such merger or consolidation; or (iii) the sale or disposition by the Company of all or substantially all of the Company’s assets in a transaction
requiring stockholder approval. “Change of Control” shall be interpreted, if applicable, in a manner, and limited to the extent necessary, so that it shall not cause adverse tax consequences under Section 409A of the Code. 

d. For purposes of this Offer Letter, “CIC Period” means the period commencing on the date that is three months prior
to the date on which a Change of Control occurs and ending on the date that is 12 months following such occurrence. 
 e. For
purposes of this Offer Letter, “Involuntary Termination” means either (a) your Termination Without Cause or (b) your Resignation for Good Reason. 

f. For purposes of this Offer Letter, “Resignation for Good Reason” means a Separation as a result of your resignation
within 12 months after one of the following conditions has come into existence without your written consent: 
 i. A
reduction in your base salary, other than in connection with an across-the-board reduction of not more than 10% effecting all similarly situated executives of the
Company; 
 ii. A material diminution of your title, authority, duties or responsibilities; 

iii. A requirement that you no longer report to the Board; 

  
 6 

 iv. A relocation of your principal workplace by more than 50 miles;
or 
 v. A material breach of this Offer Letter by the Company. 

A Resignation for Good Reason shall not be deemed to have occurred unless you give the Company written notice of the condition within 30 days
after the condition comes into existence and the Company fails to remedy the condition within 30 days after receiving your written notice. 

g. For purposes of this Offer Letter, “Separation” means a “separation from service,” as defined in the
regulations under Section 409A of the Code. 
 h. For purposes of this Offer Letter “Termination Without Cause”
means a Separation as a result of a termination of your employment by the Company without Cause, provided you are willing and able to continue performing services within the meaning of Treasury Regulation
1.409A-1(n)(1). 
 i. Any severance payments paid under this Section 3 shall commence
within 60 days after the date of termination; provided, however, that if the 60-day period begins in one calendar year and ends in a second calendar year and such severance payments constitute deferred
compensation subject to Section 409A of the Code, the severance payments begin to be paid in the second calendar year by the last day of such 60-day period; provided, further, that the initial payment
shall include a catch-up payment to cover amounts retroactive to the day immediately following the date of termination. Each payment pursuant to this Offer Letter is intended to constitute a separate payment
for purposes of Treasury Regulation Section 1.409A-2(b)(2). 
 j. Should you voluntarily
terminate your employment for any reason (other than for Good Reason) or should your employment be terminated for Cause (whether before or after a Change of Control), then you shall not be entitled to any severance payments described herein, but you
shall be entitled to the Accrued Benefits. Nothing in this Section 3 shall alter your status as an at-will employee. 

k. Vesting in the Event of a Change of Control or Death. Notwithstanding anything to the contrary hereunder or in the Equity
Plan (or any successor or other applicable equity plan) or an applicable Equity Agreement, in the event of a Change of Control or your death, then you (or your estate, as applicable) automatically shall vest in all of the then-unvested shares
subject to the equity awards under the Equity Plan (or any successor or other applicable equity plan), including, but not limited to the Sign-On Grant and the Equity-Financing Grant, as of the date of the
consummation of such Change of Control or the date of death, as applicable. 

  
 7 

 4. Certification. By signing this Offer Letter, you are certifying to the Company that:
(a) your employment with the Company does not and shall not require you to breach any agreement entered into by you prior to employment with the Company (i.e., you have not entered into any agreements with previous employers that are in
conflict with your obligations to the Company); (b) to the extent you are subject to restrictive agreements with any prior employer that may affect your employment with the Company, you have provided us with a copy of that agreement;
(c) your employment with the Company does not violate any order, judgment or injunction applicable to you, and you have provided the Company with a copy of any such order, judgment, or injunction; and (d) all facts you have presented to
the Company are accurate and true, including all statements made to the Company pertaining to your education, training, qualifications, licensing and prior work experience on any job application, resume or c.v., or in any interview. Please
understand that the Company does not want you to disclose any confidential information belonging to a previous employer or to incorporate the proprietary information of any previous employer into the Company’s proprietary information and
expects that you shall abide by restrictive covenants to prior employers. 
 5. Required I-9
Documentation. Your employment with the Company is conditioned on your eligibility to work in the United States. For purposes of completing the INS I-9 form, you must provide us sufficient documentation to
demonstrate your eligibility to work in the United States on or before your first day of employment. 
 6. Confidentiality and Other
Obligations. As part of your employment with the Company, you shall be exposed to, and provided with, valuable confidential and trade secret information concerning the Company and its present and prospective clients. As a result, in order to
protect the Company’s legitimate business interests, you agree, as a condition of your employment, to enter into the enclosed Employee Non-Solicitation, Confidentiality and Assignment Agreement (the
“Confidentiality Agreement”). You must sign and return the Confidentiality Agreement before beginning your employment with the Company. 
 7.
Section 409A and 280G of the Code. 
 a. Notwithstanding any other provision of this Offer Letter to the contrary, if any amount
(including imputed income) to be paid to you pursuant to this Offer Letter as a result of your termination of employment is “deferred compensation” subject to Section 409A of the Code, and if you are a “Specified Employee”
(as defined under Section 409A of the Code) as of the date of your termination of employment hereunder, then, to the extent necessary to avoid the imposition of excise taxes or other penalties under Section 409A of the Code, the payment of
benefits, if any, scheduled to be paid by the Company to you hereunder during the first 6-month period following the date of a termination of employment hereunder shall not be paid until the date which is the
first business day after six (6) months have elapsed since your termination of employment, or if earlier, your death. Any deferred compensation payments delayed in accordance with the terms of this Section 7.a. shall be paid in a lump sum
after 6 months have elapsed since your termination of employment. Any other payments shall be made according to the schedule provided for herein. 

  
 8 

 b. If any of the benefits set forth in this Offer Letter are “deferred
compensation” under Section 409A of the Code, any termination of employment triggering payment of such benefits must constitute a “separation from service” under Section 409A of the Code before distribution of such benefits
can commence. To the extent that the termination of your employment does not constitute a “separation from service” under Section 409A of the Code (as the result of further services that are reasonably anticipated to be provided by
you to the Company at the time your employment terminates), any benefits payable under this Offer Letter that constitute “deferred compensation” under Section 409A of the Code shall be delayed until after the date of a subsequent
event constituting a “separation from service” under Section 409A of the Code. For purposes of clarification, this Section 7.b. shall not cause any forfeiture of benefits on your part, but shall only act as a delay until such
time as a “separation from service” occurs. 
 c. It is intended that each installment of the payments and benefits
provided under this Offer Letter shall be treated as a separate “payment” for purposes of Section 409A of the Code. Neither the Company nor you shall have the right to accelerate or defer the delivery of any such payments or benefits
except to the extent specifically permitted or required by Section 409A of the Code. 
 d. This Offer Letter shall be
interpreted and at all times administered in a manner that avoids the inclusion of compensation in income under Section 409A of the Code. Any provision inconsistent with Section 409A of the Code shall be read out of the Offer Letter. For
purposes of clarification, this Section 7.d. shall be a rule of construction and interpretation and nothing in this Section 7.d. shall cause a forfeiture of benefits on the part of you. You acknowledge and agree that the Company does not
guarantee the tax treatment or tax consequences associated with any payment or benefit arising under this Offer Letter, including but not limited to consequences related to Section 409A of the Code. 

e. If any payment or benefit you would receive under this offer letter, when combined with any other payment or benefit you receive
pursuant to a Change of Control (for purposes of this section, a “Payment”) would: (i) constitute a “parachute payment” within the meaning of Section 280G the Code; and (ii) but for this sentence, be subject to the
excise tax imposed by Section 4999 of the Code (the “Excise Tax”), then, if the Company (or any affiliate that would be treated, together with the Company, as a single corporation under Section 280G of the Code and the
regulations thereunder) has stock that is readily tradeable on an established securities market (within the meaning of Section 280G of the Code and the regulations thereunder), such Payment shall be either: (A) the full amount of such
Payment; or (B) such lesser amount as would result in no portion of the Payment being subject to the Excise Tax, whichever of the foregoing amounts, taking into account the applicable federal, state and local employments taxes, income taxes and
the Excise Tax, results in your receipt, 

  
 9 

 
on an after-tax basis, of the greater amount of the Payment notwithstanding that all or some portion of the Payment may be subject to the Excise Tax. With
respect to subsection (B), if there is more than one method of reducing the payment as would result in no portion of the Payment being subject to the Excise Tax, then you shall determine which method shall be followed, provided that if you fail to
make such determination within thirty (30) days after Company has sent you written notice of the need for such reduction, Company may determine the amount of such reduction in its sole discretion. Notwithstanding the foregoing, if a Change of
Control occurs prior to the time the Company (and any affiliate that would be treated, together with the Company, as a single corporation under Section 280G of the Code and the regulations thereunder) has stock that is readily tradeable on an
established securities market (within the meaning of Section 280G of the Code and the regulations thereunder) and a Payment would constitute a parachute payment and be subject to the Excise Tax, then you and the Company or its applicable
affiliate will both cooperate in good faith with the other (including by signing any necessary waivers) to solicit a shareholder vote to approve the Payments, such that no Payment (or portion thereof) would be subject to the Excise Tax. The actions
of the Company or its applicable affiliate to this provision are not intended to bind, nor shall be construed as binding, the shareholders of the Company or its applicable affiliate. 

8. General. This Offer Letter, together with the Confidentiality Agreement and the Equity Agreements and any other agreements specifically
referred to herein, embodies the entire agreement and understanding between the parties hereto with respect to the subject matter hereof, and supersedes all prior oral or written agreements and understandings relating to the subject matter hereof.
The terms and provisions of this Offer Letter may be modified or amended only by written agreement executed by the parties hereto, and may be waived (or consent for the departure there from granted) only by a written document executed by the party
entitled to the benefits of such terms or provisions. The Company may assign its rights and obligations hereunder to any person or entity that succeeds to all or substantially of the Company’s business or assets. You may not assign your rights
and obligations hereunder without the prior written consent of the Company and any such attempted assignment by you without the prior written consent of the Company shall be void. This Offer Letter and the rights and obligations of the parties
hereunder shall be construed in accordance with and governed by the internal law of Massachusetts, without giving effect to the conflict of law principles thereof. By accepting this offer of employment, you agree that any action, demand, claim or
counterclaim in connection with any aspect of your employment with the Company, or any separation of employment (whether voluntary or involuntary) from the Company, shall be brought in the courts of Massachusetts or of the United States of America
for the District of Massachusetts, and shall be resolved by a judge alone, and you waive and forever renounce your right to a trial before a civil jury. 

9. Indemnification. To the fullest extent permitted by the applicable D&O policies of the Company and/or applicable law regarding
indemnification, the Company shall indemnify 

  
 10 

 
you against all expenses (including reasonable attorneys’ fees and any expenses incurred in establishing a right to indemnification), judgments, fines, settlements and other amounts actually
and reasonably incurred by you in connection with any threatened, pending or completed action or proceeding, whether civil, criminal, administrative, or investigative that you is made a party to by reason of the fact that you are or were performing
services as an employee, officer, director or agent of the Company or any affiliate thereof, subject to the terms of this Section 9. In addition, such indemnification shall continue as to you even if you have ceased to be an employee, officer,
director or agent of the Company and/or any affiliate thereof and shall inure to the benefit of your heirs and estate. The provisions of this Section 9 are in addition to, and not in derogation of, the indemnification provisions of the bylaws
and certificate or articles of incorporation of the Company or any affiliate thereof, as each may be amended or restated from time to time. During your employment with the Company and/or any affiliate thereof and from and after the date that your
employment is terminated for any reason whatsoever, you shall receive the same benefits provided to any of the officers and directors of the Company or such affiliate, as applicable, under any additional D&O insurance or similar policy,
indemnification agreement, policy of the Company or such applicable affiliate or the articles of incorporation or bylaws of the Company or such applicable affiliate, in each case, as may be amended or restated from time to time. This Section 9
shall survive the termination of this Offer Letter. 
 Because our employment discussions and the terms of your employment are confidential, it is
understood that you shall not disclose the fact or terms of such discussions or the terms of your employment with the Company to anyone other than your immediate family and your legal or financial advisor at any time, absent prior written consent
from the Company, or as permitted by law. 
 [Signature Page Follows] 

  
 11 

 This offer shall remain open, unless sooner revoked by the Company, through March 8, 2019. Please
acknowledge acceptance of this employment offer by signing and dating below. Keep one copy for your files and return one executed copy to me. 
 Mahesh, we
greatly look forward to having you on the team. 
  

			
	Very truly yours,
	
	Omega Therapeutics
		
	By:	 	 /s/ David Berry

		 	David Berry

  

	
	Accepted and Agreed to:
	
	 /s/ Mahesh Karande

	
	 Mahesh Karande

	Date: March 2, 2019

  
 12EX-10.6

 Exhibit 10.6 
  

 
 July 10, 2019 
 Tom
McCauley 
 [XXX] 
 [XXX] 

Dear Tom, 
 On behalf of Omega Therapeutics,
Inc. (the “Company”), a Flagship Pioneering Company, I am delighted to make this conditional offer of employment with the Company. This offer letter (the “Offer Letter”) and the accompanying documents and agreements summarize and
set forth important terms about your employment with the Company. 
 1. Starting Date, Position, and Duties. 

a. Your initial position shall be Chief Scientific Officer reporting to the Company’s CEO. We anticipate that your
employment shall start effective July 29, 2019 (the “Start Date”). 
 b. As a member of our team,
we expect you to devote all of your professional and working time and energies to the business and affairs of the Company. Notwithstanding the forgoing, nothing contained herein shall prevent you from managing your personal investments on your own
personal time, including the right to make passive investments in the securities of: (i) any entity which you do not control, directly or indirectly, and which does not compete with Company, and (ii) any
publicly held entity so long as your aggregate direct and indirect interest does not exceed five percent (5%) of the issued and outstanding securities of any class of securities of such publicly held entity. You shall not engage in other non-Company related business activities (including board memberships) without Company’s prior written consent, which consent shall not be unreasonably withheld, conditioned or delayed. 

c. As is generally true for Company employees, you shall be employed on an at-will basis, which
means that neither you nor the Company are guaranteeing this employment relationship for any specific period of time. Either of you or the Company may choose to end the employment relationship at any time, for any reason, with or without notice. The
descriptions of benefits and other compensation arrangements set forth herein are meant to be summary in form and may be subject to change. Other than the terms of this Offer Letter, the Company reserves the right to alter, supplement or rescind its
employment procedures, benefits or policies (other than the employment at-will policy) at any time in its sole and absolute discretion and without notice. 

  
 1 

 

 
  
 2. Compensation. 

a. Salary. Your initial base pay shall be at a rate of $350,000 on an annualized basis, minus customary deductions for federal
and state taxes and the like, paid in accordance with the Company’s normal payroll practices (the “Annual Salary”). 

b. Annual Performance Bonus. You shall be eligible to receive an annual bonus of up to thirty-five percent (35%) of your Annual
Salary (the “Annual Bonus”), payable upon the achievement, as determined by the Company’s Board of Directors (the “Board”) in its sole discretion, of specific milestones to be mutually agreed in writing. The Annual Bonus
shall be paid to you no later than March 15th of the calendar year immediately following the calendar year in which it was earned. You must be employed by the Company at the time that the Annual
Bonus is paid in order to be eligible for the Annual Bonus. 
 c. Equity; Stock Options. I shall ask the Board to grant
you an option or other equivalent instrument (the “Equity Grant”) to purchase shares of common stock or equivalent equity incentive units of the Company equal to 1.4% ( 1,114,053 shares) of the fully diluted equity of the Company
determined as of the Start Date, at a strike price equal to the fair market value of the Company’s common stock or equivalent equity incentive units on the date of grant as determined by the Board. Any grant shall be subject to quarterly
vesting, over a four-year period beginning on your first date of employment, subject to a one-year cliff (i.e., 25% of the grant shall vest on the first year anniversary of the Start Date). In all respects,
these options shall be governed by the Company’s equity incentive plan and applicable grant agreement then in effect. 
 d.
Benefits. You shall be eligible to participate in the Company’s benefit plans to the same extent as, and subject to the same terms, conditions and limitations applicable to, senior executives of the Company. Summaries of each of the
Company’s benefit plans are available to you. These benefits may be modified, changed or eliminated from time to time at the sole discretion of the Company, and the provision of such benefits does not change your status as an at-will employee. Where a particular benefit is subject to a formal plan (for example, medical insurance or life insurance), eligibility to participate in and receive any particular benefit is governed solely by the
applicable plan document. Each calendar year you shall be eligible to accrue four (4) weeks’ vacation and holidays as set forth by the Company and subject to the Company’s vacation and holiday policies as in effect from time to time.

 e. Expense Reimbursement. The Company shall reimburse you for all ordinary and reasonable out-of-pocket business expenses incurred in furtherance of the Company’s business in accordance with the Company’s policies with respect thereto as in effect from time to time. You must submit any
request for reimbursement no later than ninety (90) days following the date that such business expense is incurred. All reimbursements hereunder shall be made or provided in accordance with the requirements of Section 409A
(“Section 409A”) of the Internal Revenue 

  
 2 

 

 
  
 Code and the rules and regulations thereunder (the
“Code”) including, where applicable, the requirement that: (i) any reimbursement is for expenses incurred during your lifetime (or during a shorter period of time specified in this Offer Letter); (ii) the
amount of expenses eligible for reimbursement during a calendar year may not affect the expenses eligible for reimbursement in any other calendar year; (iii) the reimbursement of an eligible expense shall be made no later than the
last day of the calendar year following the year in which the expense is incurred; and (iv) the right to reimbursement or in kind benefits is not subject to liquidation or exchange for another benefit. 

f. Accrued Obligations. For purposes of this Offer Letter, “Accrued Obligations” means: (i) the portion of your
Annual Salary that has accrued prior to any termination of your employment with the Company and has not yet been paid; (ii) any accrued but unused vacation time pursuant to the Company’s standard policy and practices, and (iii) the
amount of any reimbursable expenses properly incurred by you on behalf of the Company prior to any such termination and not yet reimbursed. You shall be paid the Accrued Obligations upon or promptly following any termination of your employment with
the Company. 
 3. Severance Benefit upon Termination without Cause. 

a. Notwithstanding the at-will nature of the parties’ relationship, should the Company
terminate your employment without Cause (as defined below), or should you terminate your employment with the Company for Good Reason (as defined below), you shall be paid the Accrued Obligations promptly upon such termination. In addition,
conditioned upon: (i) your execution within 45 days after the date of your employment termination and non-revocation of and compliance with a separation agreement which shall contain, among
other things, a full and general release of claims to the Company and its affiliates and their respective directors, officers, agents and employees, in a form reasonably satisfactory to the Company, and if your termination is by the Company without
Cause, a non-competition covenant that restricts certain competitive activities for a period of one (1) year from the date of termination (provided that if your termination does not qualify as Cause
hereunder but qualifies as “Cause” as defined in your Non-Competition Agreement (as defined in Section 6 below), the non-competition covenant will not be
contained in the separation agreement, but rather in your Non-Competition Agreement, with which you will be expected to comply) and (ii) your compliance with your obligations set forth in
your Employee Non-Solicitation, Confidentiality and Assignment Agreement (the “Confidentiality Agreement” as described in Section 6 below), then the Company shall provide you with:
(iii) payments equal to six (6) months of your then current base salary, payable in periodic installments over six (6) months, in accordance with the Company’s normal payroll practices; (iv) any unpaid
Annual Bonus the Board determines was earned by you for the year prior to the year in which your employment termination occurs, payable in a lump sum at substantially the same time at which annual bonuses for such year are paid to other Company
senior executives (but in no event later than December 31 of the year in which your employment termination occurs); and (v) (x) if the Company is subject to the Consolidated Omnibus Budget

  
 3 

 

 
  
 Reconciliation Act (“COBRA”) or similar
state law, (y) the premium subsidy described below is not illegal or discriminatory under the Code, the Patient Protection and Affordable Care Act or the Health Care and Education Reconciliation Act, and (z) if you properly elect to
receive benefits under COBRA, six (6) months of your COBRA premiums at the Company’s normal rate of contribution for employees for your coverage at the level in effect immediately prior to your termination. 

b. For purposes of this Section 3, “Cause” means any one or more of the following actions: (i) your material
breach of the terms of this Offer Letter, your Confidentiality Agreement, or your Non-Competition Agreement, to the extent capable of cure, following written notice of such material breach by the Company and a
period of thirty (30) days to cure the same; (ii) your material dishonesty, willful misconduct, gross negligence, or reckless conduct; (iii) your commission of an act of fraud, theft, misappropriation or
embezzlement; (iv) your conviction of, or pleading nolo contendere to, any crime involving dishonesty or moral turpitude or any felony; or (v) your material violation of a Company policy or willful refusal to perform your
assigned duties to the Company, to the extent capable of cure, following written notice of such violation or refusal by the Company and a period of thirty (30) days to cure the same. 

c. For purposes of this Section 3, “Good Reason” shall mean (i) relocation of your office location to a location
more than fifty (50) miles from your office location on the Start Date, (ii) a material diminution in your duties, authority or responsibilities, other than in connection with a corporate transaction immediately after which you continue to
hold substantially the same positon with respect to the Company’s business, substantially as such business exists prior to such corporate transaction, as you held immediately before such corporate transaction but do not hold such position with
respect to the successor or surviving entity, (iii) a material reduction in your Annual Salary, other than such a reduction that is implemented in connection with a contemporaneous and proportionate reduction in annual base salaries affecting
all other senior executives of the Company, or (iv) material breach by the Company of its covenants and/or obligations under this Offer Letter; provided that, in each of the foregoing clauses (i) through (iv), (A) you provide the
Company with written notice that you intend to terminate your employment hereunder for one or more of the grounds set forth in this Section 3.c. within thirty (30) days of the occurrence of the event constituting a ground for Good Reason
termination, (B) if such ground is capable of being cured, the Company has failed to cure such ground within a period of thirty (30) days from the date of such written notice, and (C) you terminate by written notice your employment
within sixty (60) days from the date you provide the notice described in clause (A) of this Section 3.c. 
 d. Any
severance payments paid under this Section 3 shall commence within 60 days after the date of termination; provided, however, that if the 60-day period begins in one calendar year and ends in a second
calendar year, the severance payments will begin to be paid in the second calendar year by the last day of such 60-day period; provided, further, that the initial payment shall include a catch-up payment to cover amounts retroactive to the day immediately following the date of termination. Each payment pursuant to this Agreement is intended to constitute a separate payment for purposes of Treasury
Regulation Section 1.409A-2(b)(2). 

  
 4 

 

 
  
 e. Should you voluntarily
terminate your employment for any reason other than Good Reason, or should your employment be terminated for Cause, then you shall not be entitled to any severance payments described herein. Nothing in this Section 3 shall alter your status as
an at-will employee. 
 4. Certification. By signing this Offer Letter, you are certifying to the
Company that: (a) your employment with the Company does not and shall not require you to breach any agreement entered into by you prior to employment with the Company (i.e., you have not entered into any agreements with previous
employers that are in conflict with your obligations to the Company); (b) to the extent you may be subject to restrictive agreements with any prior employer that may affect your employment with the Company, you have provided us with a copy of
that agreement; (c) your employment with the Company does not violate any order, judgment or injunction applicable to you, and you have provided the Company with a copy of any such order, judgment, or injunction; and
(d) all facts you have presented to the Company are accurate and true, including all statements made to the Company pertaining to your education, training, qualifications, licensing and prior work experience on any job application,
resume or c.v., or in any interview. Please understand that the Company does not want you to disclose any confidential information belonging to a previous employer or to incorporate the proprietary information of any previous employer into
the Company’s proprietary information and expects that you shall abide by restrictive covenants to prior employers. 
 5. Required I-9 Documentation. Your employment with the Company is conditioned on your eligibility to work in the United States. For purposes of completing the INS I-9 form, you must
provide us sufficient documentation to demonstrate your eligibility to work in the United States on or before your first day of employment. 
 6.
Confidentiality and Other Obligations. As part of your employment with the Company, you shall be exposed to, and provided with, valuable confidential and trade secret information concerning the Company and its present and prospective clients.
As a result, in order to protect the Company’s legitimate business interests, you understand that your employment by the Company creates a relationship of confidence with respect to confidential and proprietary information belonging to the
Company and third parties. In light of the foregoing and as a condition of your employment, you must sign and abide by: (a) the Company’s standard Confidentiality Agreement, and (b) the Company’s standard
Noncompetition Agreement (the “Non-Competition Agreement”), and (c) the Company’s standard Waiver of Review Period (the “Waiver”), copies of which are enclosed. As a Company
employee, you shall be expected to abide by Company policies and procedures as may be in effect from time to time. You must sign and return the Confidentiality Agreement, Noncompetition Agreement, and Waiver (if applicable) before beginning your
employment with the Company. 

  
 5 

 

 
  
 7. Section 409A of the Code. 

a. Notwithstanding any other provision of this Offer Letter to the contrary, if any amount (including imputed income) to be paid to you
pursuant to this Offer Letter as a result of your termination of employment is “deferred compensation” subject to Section 409A of the Code, and if you are a “Specified Employee” (as defined under Section 409A of the
Code) as of the date of your termination of employment hereunder, then, to the extent necessary to avoid the imposition of excise taxes or other penalties under Section 409A of the Code, the payment of benefits, if any, scheduled to be paid by
the Company to you hereunder during the first 6-month period following the date of a termination of employment hereunder shall not be paid until the date which is the first business day after six
(6) months have elapsed since your termination of employment for any reason other than death. Any deferred compensation payments delayed in accordance with the terms of this Section 6.a. shall be paid in a lump sum after 6-months have elapsed since your termination of employment. Any other payments shall be made according to the schedule provided for herein. 

b. If any of the benefits set forth in this Offer Letter are “deferred compensation” under Section 409A of the Code, any
termination of employment triggering payment of such benefits must constitute a “separation from service” under Section 409A of the Code before distribution of such benefits can commence. To the extent that the termination of your
employment does not constitute a “separation from service” under Section 409A of the Code (as the result of further services that are reasonably anticipated to be provided by you to the Company at the time your employment terminates),
any benefits payable under this Offer Letter that constitute “deferred compensation” under Section 409A of the Code shall be delayed until after the date of a subsequent event constituting a “separation from service” under
Section 409A of the Code. For purposes of clarification, this Section 6.b. shall not cause any forfeiture of benefits on your part, but shall only act as a delay until such time as a “separation from service” occurs. 

c. It is intended that each installment of the payments and benefits provided under this Offer Letter shall be treated as a separate
“payment” for purposes of Section 409A of the Code. Neither the Company nor you shall have the right to accelerate or defer the delivery of any such payments or benefits except to the extent specifically permitted or required by
Section 409A of the Code. 
 d. This Offer Letter shall be interpreted and at all times administered in a manner that avoids the
inclusion of compensation in income under Section 409A of the Code. Any provision inconsistent with Section 409A of the Code shall be read out of the Offer Letter, to the extent that such inconsistent provision can be read out without
violation of Section 409A. For purposes of clarification, this Section 6.d. shall be a rule of construction and interpretation and nothing in this Section 6.d. shall cause a forfeiture of benefits on the part of you.

  
 6 

 

 
  
 You acknowledge and agree that the Company does not
guarantee the tax treatment or tax consequences associated with any payment or benefit arising under this Offer Letter, including but not limited to consequences related to Section 409A of the Code. 

8. Indemnification. Following the Start Date and during your employment, you will be entitled to indemnification for claims arising out of your
employment hereunder to the same extent as other senior executives of the Company. 
 9. General. This Offer Letter, together with the
Confidentiality Agreement and any other written agreements specifically referred to herein, embodies the entire agreement and understanding between the parties hereto with respect to the subject matter hereof, and supersedes all prior oral or
written agreements and understandings relating to the subject matter hereof. The terms and provisions of this Offer Letter may be modified or amended only by written agreement executed by the parties hereto, and may be waived (or consent for the
departure there from granted) only by a written document executed by the party entitled to the benefits of such terms or provisions. The Company may assign its rights and obligations hereunder to any person or entity that succeeds to all or
substantially all of the Company’s business. You may not assign your rights and obligations hereunder without the prior written consent of the Company and any such attempted assignment by you without the prior written consent of the Company
shall be void. This Offer Letter and the rights and obligations of the parties hereunder shall be construed in accordance with and governed by the internal law of Massachusetts, without giving effect to the conflict of law principles thereof. By
accepting this offer of employment, you agree that any action, demand, claim or counterclaim in connection with any aspect of your employment with the Company, or any separation of employment (whether voluntary or involuntary) from the Company,
shall be brought in the courts of Massachusetts or of the United States of America for the District of Massachusetts, and shall be resolved by a judge alone, and you waive and forever renounce your right to a trial before a civil jury. 

Because our employment discussions and the terms of your employment are confidential, it is understood that you shall not disclose the fact or
terms of such discussions or the terms of your employment with the Company to anyone other than your immediate family and your legal or financial advisor at any time, absent prior written consent from the Company, or as permitted by law. 

This offer shall remain open, unless sooner revoked by the Company, through July 20, 2019. Please acknowledge
acceptance of this employment offer by signing and dating below. Keep one copy for your files and return one executed copy to me. 

[Signature Page Follows] 

  
 7 

 

 
  
 Tom, we look forward to having you on the team. 

Very truly yours, 

Omega Therapeutics, Inc. 

/s/ Mahesh Karande 

Mahesh Karande, President & CEO 
  

	
	Accepted and Agreed to:
	
	 /s/ Tom McCauley

	Tom McCauley
	
	 7/14/19

	Date

  
 8

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00330-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00330-of-00352.parquet"}]]