Exhibit 10.5


 


October
21, 2020


 


Yellowstone
Acquisition Company


1411
Harney Street, Suite 200

Omaha, Nebraska 68102


 


Re: Initial
Public Offering


 


Ladies
and Gentlemen:


 


This
letter agreement (this “Letter Agreement”) is being delivered to you in accordance with the Underwriting
Agreement (the “Underwriting Agreement”) to be entered into by and between Yellowstone Acquisition Company,
a Delaware corporation (the “Company”), and Wells Fargo Securities, LLC, as representative (the “Representative”)
of the several underwriters (each, an “Underwriter” and collectively, the “Underwriters”),
relating to an underwritten initial public offering (the “Public Offering”), of 12,500,000 of the Company’s
units (including up to 1,875,000 units that may be purchased to cover over-allotments, if any) (the “Units”),
each comprised of one share of the Company’s Class A common stock, par value $0.0001 per share (the “Common
Stock”), and one-half of one warrant. Each whole warrant (each, a “Warrant”) entitles
the holder thereof to purchase one share of Common Stock at a price of $11.50 per share, subject to adjustment. The Units shall
be sold in the Public Offering pursuant to a registration statement on Form S-1 and prospectus (the “Prospectus”)
filed by the Company with the Securities and Exchange Commission (the “Commission”), and the Company
shall apply to have the Units listed on the NASDAQ Capital Market. Certain capitalized terms used herein are defined in paragraph
11 hereof.


 


In
order to induce the Company and the Underwriters to enter into the Underwriting Agreement and to proceed with the Public Offering
and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, BOC Yellowstone,
LLC (the “Sponsor”) and each of the undersigned individuals, each of whom is a member of the Company’s
board of directors and/or management team (each, an “Insider” and collectively, the “Insiders”),
hereby agrees with the Company as follows:


 


1.  The
Sponsor and each Insider agrees that if the Company seeks stockholder approval of a proposed Business Combination, then in connection
with such proposed Business Combination, it, he or she shall (i) vote any shares of Capital Stock owned by it, him or her in favor
of any proposed Business Combination and (ii) not redeem any shares of Common Stock owned by it, him or her in connection with
such stockholder approval.


 




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2.  The
Sponsor and each Insider hereby agrees that in the event that the Company fails to consummate a Business Combination within fifteen
(15) months from the closing of the Public Offering, or such later period as may be approved by the Company’s stockholders
in accordance with the Company’s amended and restated certificate of incorporation, the Sponsor and each Insider shall take
all reasonable steps to cause the Company to (i) cease all operations except for the purpose of winding up, (ii) as promptly as
reasonably possible but not more than ten (10) business days thereafter, subject to lawfully available funds therefor, redeem
100% of the Common Stock sold as part of the Units in the Public Offering (the “Offering Shares”), at
a per-share price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account, including interest earned
on the funds held in the Trust Account and not previously released to the Company to pay its franchise and income taxes as well
as any expenses related to the administration of the Trust Account (less up to $100,000 of interest to pay dissolution expenses),
divided by the number of then outstanding Offering Shares, which redemption will completely extinguish all of the Public Stockholders’
rights as stockholders (including the right to receive further liquidation distributions, if any), subject to applicable law and
(iii) as promptly as reasonably possible following such redemption, subject to the approval of the Company’s remaining stockholders
and the Company’s board of directors, dissolve and liquidate, subject in each case to the Company’s obligations under
Delaware law to provide for claims of creditors and other requirements of applicable law. The Sponsor and each Insider agree not
to propose any amendment to the Company’s amended and restated certificate of incorporation (x) that would modify the substance
or timing of the Company’s obligation to redeem 100% of the Offering Shares if the Company does not complete a Business
Combination within fifteen (15) months from the closing of the Public Offering, or (y) with respect to any other provision relating
to stockholders’ rights or pre-initial Business Combination activity, unless the Company provides its Public Stockholders
with the opportunity to redeem their Offering Shares upon approval of any such amendment at a per-share price, payable in cash,
equal to the aggregate amount then on deposit in the Trust Account, including interest not previously released to the Company
to pay its franchise and income taxes as well as any expenses related to the administration of the Trust Account, divided by the
number of then outstanding Offering Shares.


 


The
Sponsor and each Insider acknowledges that it, he or she has no right, title, interest or claim of any kind in or to any monies
held in the Trust Account or any other asset of the Company as a result of any liquidation of the Company with respect to the
Founder Shares held by it, him or her. The Sponsor and each Insider hereby further waives, with respect to any shares of Common
Stock held by it, him or her, if any, any redemption rights it, he or she may have in connection with the consummation of a Business
Combination, including, without limitation, any such rights available in the context of a stockholder vote to approve such Business
Combination or in the context of a tender offer made by the Company to purchase shares of Common Stock (although the Sponsor,
the Insiders and their respective affiliates shall be entitled to redemption and liquidation rights with respect to any Offering
Shares it, he, she or they hold if the Company fails to consummate a Business Combination within fifteen (15) months from the
date of the closing of the Public Offering).


 


3.  During
the period commencing on the effective date of the Underwriting Agreement and ending one hundred eighty (180) days after such
date, the Sponsor and each Insider shall not, without the prior written consent of the Representative, (i) sell, offer to sell,
contract or agree to sell, hypothecate, pledge, grant any option to purchase or otherwise dispose of or agree to dispose of, directly
or indirectly, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the
meaning of Section 16 of the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission promulgated
thereunder, with respect to any Units, shares of Common Stock, Founder Shares, Warrants or any securities convertible into, or
exercisable, or exchangeable for, shares of Common Stock owned by it, him or her, (ii) enter into any swap or other arrangement
that transfers to another, in whole or in part, any of the economic consequences of ownership of any Units, shares of Common Stock,
Founder Shares, Warrants or any securities convertible into, or exercisable, or exchangeable for, shares of Common Stock owned
by it, him or her, whether any such transaction is to be settled by delivery of such securities, in cash or otherwise or (iii)
publicly announce any intention to effect any transaction specified in clause (i) or (ii). The provisions of this paragraph will
not apply if the release or waiver is effected solely to permit a transfer not for consideration and the transferee has agreed
in writing to be bound by the same terms described in this Letter Agreement to the extent and for the duration that such terms
remain in effect at the time of the transfer.


 




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4.  In
the event of the liquidation of the Trust Account, the Sponsor (which for purposes of clarification shall not extend to any other
shareholders, members or managers of the Sponsor) agrees to indemnify and hold harmless the Company against any and all loss,
liability, claim, damage and expense whatsoever (including, but not limited to, any and all legal or other expenses reasonably
incurred in investigating, preparing or defending against any litigation, whether pending or threatened, or any claim whatsoever)
to which the Company may become subject as a result of any claim by (i) any third party for services rendered or products sold
to the Company or (ii) a prospective target business with which the Company has entered into an acquisition agreement or discussed
entering into an acquisition agreement (a “Target”); provided, however, that
such indemnification of the Company by the Sponsor shall apply only to the extent necessary to ensure that such claims by a third
party for services rendered or products sold to the Company or by a Target do not reduce the amount of funds in the Trust Account
to below (i) $10.00 per Offering Share or (ii) such lesser amount per Offering Share held in the Trust Account due to reductions
in the value of the trust assets as of the date of the liquidation of the Trust Account, in each case, net of the amount of interest
earned on the property in the Trust Account which may be withdrawn to pay taxes and expenses related to the administration of
the Trust Account, except as to any claims by a third party (including a Target) who executed a waiver of any and all rights to
seek access to the Trust Account and except as to any claims under the Company’s indemnity of the Underwriters against certain
liabilities, including liabilities under the Securities Act of 1933, as amended. In the event that any such executed waiver is
deemed to be unenforceable against such third party, the Sponsor shall not be responsible to the extent of any liability for such
third party claims. The Sponsor shall have the right to defend against any such claim with counsel of its choice reasonably satisfactory
to the Company if, within fifteen (15) days following written receipt of notice of the claim to the Sponsor, the Sponsor notifies
the Company in writing that it shall undertake such defense.


 


5.  To
the extent that the Underwriters do not exercise their over-allotment option to purchase up to an additional 1,875,000 Units within
forty-five (45) days from the date of the Prospectus (and as further described in the Prospectus), the Sponsor agrees to forfeit,
at no cost, a number of Founder Shares in the aggregate equal to 468,750 multiplied by a fraction, (i) the numerator of which
is 3,593,750 minus the number of Units purchased by the Underwriters upon the exercise of their over-allotment option, and (ii)
the denominator of which is 3,593,750. The forfeiture will be adjusted to the extent that the over-allotment option is not exercised
in full by the Underwriters so that the Initial Stockholders will own an aggregate of twenty percent (20.0%) of the Company’s
issued and outstanding shares of Capital Stock after the Public Offering.


 


6.  The
Sponsor and each Insider hereby agrees and acknowledges that: (i) the Underwriters and the Company would be irreparably injured
in the event of a breach by such Sponsor or Insider of its, his or her obligations under paragraphs 1, 2, 3, 4, 5, 7(a), 7(b),
and 9 of this Letter Agreement, (ii) monetary damages may not be an adequate remedy for such breach and (iii) the non-breaching
party shall be entitled to injunctive relief, in addition to any other remedy that such party may have in law or in equity, in
the event of such breach.


 




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7.  (a)  The
Sponsor and each Insider agrees that it, he or she shall not Transfer any Founder Shares (or shares of Common Stock issuable
upon conversion thereof) until the earlier of (A) one year after the completion of the Company’s initial Business Combination
or (B) subsequent to the Business Combination, (x) if the last sale price of the Common Stock equals or exceeds $12.00 per share
(as adjusted for stock splits, stock dividends, reorganizations, recapitalizations and the like) for any twenty (20) trading days
within any thirty (30)-trading day period commencing at least one hundred fifty (150) days after the Company’s initial Business
Combination or (y) the date on which the Company completes a liquidation, merger, capital stock exchange, reorganization or other
similar transaction that results in all of the Company’s stockholders having the right to exchange their shares of Common
Stock for cash, securities or other property (the “Founder Shares Lock-up Period”).


 


(b)  The
Sponsor and each Insider agrees that it, he or she shall not Transfer any Private Placement Warrants (or shares of Common Stock
issued or issuable upon the exercise of the Private Placement Warrants), until thirty (30) days after the completion of a Business
Combination (the “Private Placement Warrants Lock-up Period” and, together with the Founder Shares Lock-up
Period, the “Lock-up Periods”).


 


(c)  Notwithstanding
the provisions set forth in paragraphs 7(a) and (b), Transfers of the Founder Shares, Private Placement Warrants and shares of
Common Stock issued or issuable upon the exercise or conversion of the Private Placement Warrants or the Founder Shares, as applicable,
and that are held by the Sponsor, an Insider or any of their permitted transferees (that have complied with this paragraph 7(c)),
are permitted (a) to the Company’s officers, directors, any affiliates or family members of any of the Company’s officers,
directors, any members of the Sponsor or any affiliates of the Sponsor; (b) in the case of an individual, transfers by gift to
a member of the individual’s immediate family, to a trust, the beneficiary of which is a member of the individual’s
immediate family or an affiliate of such person, or to a charitable organization; (c) in the case of an individual, transfers
by virtue of laws of descent and distribution upon death of the individual; (d) in the case of an individual, transfers pursuant
to a qualified domestic relations order; (e) transfers by private sales or transfers made in connection with the consummation
of a Business Combination at prices no greater than the price at which the securities were originally purchased; (f) transfers
in the event of the Company’s liquidation prior to the completion of an initial Business Combination; (g) transfers by virtue
of the laws of the State of Delaware or the Sponsor’s limited liability company agreement upon dissolution of the Sponsor;
and (h) in the event of the Company’s liquidation, merger, capital stock exchange, reorganization or other similar transaction
which results in all of the Company’s stockholders having the right to exchange their shares of Common Stock for cash, securities
or other property subsequent to the completion of the Company’s initial Business Combination; provided, however, that in
the case of clauses (a) through (g), these permitted transferees must enter into a written agreement agreeing to be bound by the
restrictions herein.


 




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8.  The
Sponsor and each Insider represents and warrants that it, he or she has never been suspended or expelled from membership in any
securities or commodities exchange or association or had a securities or commodities license or registration denied, suspended
or revoked. Each Insider’s biographical information furnished to the Company (including any such information included in
the Prospectus) is true and accurate in all respects and does not omit any material information with respect to the Insider’s
background. The questionnaire of the Sponsor and each Insider furnished to the Company is true and accurate in all respects. The
Sponsor and each Insider represents and warrants that: it, he or she is not subject to or a respondent in any legal action for,
any injunction, cease-and-desist order or order or stipulation to desist or refrain from any act or practice relating to the offering
of securities in any jurisdiction; it, he or she has never been convicted of, or pleaded guilty to, any crime (i) involving fraud,
(ii) relating to any financial transaction or handling of funds of another person or (iii) pertaining to any dealings in
any securities and it, he or she is not currently a defendant in any such criminal proceeding.


 


9.  Except
as disclosed in the Prospectus, neither the Sponsor nor any Insider nor any affiliate of the Sponsor or any Insider, nor any director
or officer of the Company, shall receive from the Company any finder’s fee, reimbursement, consulting fee, monies in respect
of any repayment of a loan or other compensation prior to, or in connection with any services rendered in order to effectuate
the consummation of the Company’s initial Business Combination (regardless of the type of transaction that it is), other
than the following, none of which will be made from the proceeds held in the Trust Account prior to the completion of the initial
Business Combination: (a) reimbursement for any out-of-pocket expenses related to the Company’s formation and Public Offering
and to identifying, investigating and completing an initial Business Combination; (b) repayment of loans, if any, and on such
terms as to be determined by the Company from time to time, made by the Sponsor or any of the Company’s officers or directors
to finance transaction costs in connection with an intended initial Business Combination, provided, that, if the Company does
not consummate an initial Business Combination, a portion of the working capital held outside the Trust Account may be used by
the Company to repay such loaned amounts so long as no proceeds from the Trust Account are used for such repayment; and (c) payments
to the Sponsor, any Insiders or their respective affiliates in connection with the successful completion of the Company’s
initial Business Combination. Up to $1,500,000 of the loans referenced in clause (b) above may be convertible into warrants at
a price of $1.50 per warrant at the option of the lender. Such warrants would be identical to the Private Placement Warrants,
including as to exercise price, exercisability and exercise period.


 


10.  The
Sponsor and each Insider has full right and power, without violating any agreement to which it is bound (including, without limitation,
any non-competition or non-solicitation agreement with any employer or former employer), to enter into this Letter Agreement and,
as applicable, to serve as an officer and/or a director on the board of directors of the Company and hereby consents to being
named in the Prospectus as an officer and/or director of the Company.


 




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11.  As
used herein, (i) “Business Combination” shall mean a merger, capital stock exchange, asset acquisition,
stock purchase, reorganization or similar business combination, involving the Company and one or more businesses; (ii) “Capital
Stock” shall mean, collectively, the Common Stock and the Founder Shares; (iii) “Founder Shares”
shall mean the 3,593,750 shares of the Company’s Class B common stock, par value $0.0001 per share, (of which 468,750 shares
will be forfeited by the Sponsor if the over-allotment option is not exercised by the Underwriters) owned by the Initial Stockholders;
(iv) “Initial Stockholders” shall mean the Sponsor and other holders of Founder Shares immediately prior
to the Public Offering; (v) “Private Placement Warrants” shall mean the warrants to purchase
up to 7,500,000 shares of Common Stock of the Company (or 7,875,000 shares of Common Stock if the over-allotment option is exercised
in full) that the Sponsor agreed to purchase for an aggregate purchase price of $7,500,000 in the aggregate (or $7,875,000 if
the over-allotment option is exercised in full), for $1.00 per warrant, in a private placement that shall occur simultaneously
with the consummation of the Public Offering; (vi) “Public Stockholders” shall
mean the holders of securities issued in the Public Offering; (vii) “Trust Account” shall
mean the trust account into which a portion of the net proceeds of the Public Offering and the sale of the Private Placement Warrants
shall be deposited; and (viii) “Transfer” shall mean the (a) sale of, offer to sell, contract
or agreement to sell, hypothecate, pledge, grant of any option to purchase or otherwise dispose of or agreement to dispose of,
directly or indirectly, or establishment or increase of a put equivalent position or liquidation with respect to or decrease of
a call equivalent position within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, and the rules
and regulations of the Commission promulgated thereunder with respect to, any security, (b) entry into any swap or other arrangement
that transfers to another, in whole or in part, any of the economic consequences of ownership of any security, whether any such
transaction is to be settled by delivery of such securities, in cash or otherwise, or (c) public announcement of any intention
to effect any transaction specified in clause (a) or (b).


 


12.  This
Letter Agreement constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof
and supersedes all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the
extent they relate in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may
not be changed, amended, modified or waived (other than to correct a typographical error) as to any particular provision, except
by a written instrument executed by all parties hereto.


 


13.  No
party hereto may assign either this Letter Agreement or any of its rights, interests, or obligations hereunder without the prior
written consent of the other parties. Any purported assignment in violation of this paragraph shall be void and ineffectual and
shall not operate to transfer or assign any interest or title to the purported assignee. This Letter Agreement shall be binding
on the Sponsor and each Insider and their respective successors, heirs and assigns and permitted transferees.


 


14.  Nothing
in this Letter Agreement shall be construed to confer upon, or give to, any person or corporation other than the parties hereto
any right, remedy or claim under or by reason of this Letter Agreement or of any covenant, condition, stipulation, promise or
agreement hereof. All covenants, conditions, stipulations, promises and agreements contained in this Letter Agreement shall be
for the sole and exclusive benefit of the parties hereto and their successors, heirs, personal representatives and assigns and
permitted transferees.


 


15.  This
Letter Agreement may be executed in any number of original or facsimile counterparts and each of such counterparts shall for all
purposes be deemed to be an original, and all such counterparts shall together constitute but one and the same instrument.


 


16.  This
Letter Agreement shall be deemed severable, and the invalidity or unenforceability of any term or provision hereof shall not affect
the validity or enforceability of this Letter Agreement or of any other term or provision hereof. Furthermore, in lieu of any
such invalid or unenforceable term or provision, the parties hereto intend that there shall be added as a part of this Letter
Agreement a provision as similar in terms to such invalid or unenforceable provision as may be possible and be valid and enforceable.


 




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17.  This
Letter Agreement shall be governed by and construed and enforced in accordance with the laws of the State of Delaware, without
giving effect to conflicts of law principles that would result in the application of the substantive laws of another jurisdiction.
The parties hereto (i) all agree that any action, proceeding, claim or dispute arising out of, or relating in any way to, this
Letter Agreement shall be brought and enforced in the courts of Delaware in the State of Delaware, and irrevocably submit to such
jurisdiction and venue, which jurisdiction and venue shall be exclusive and (ii) waive any objection to such exclusive jurisdiction
and venue or that such courts represent an inconvenient forum.


 


18.  Any
notice, consent or request to be given in connection with any of the terms or provisions of this Letter Agreement shall be in
writing and shall be sent by express mail or similar private courier service, by certified mail (return receipt requested), by
hand delivery or facsimile transmission.


 


19.  This
Letter Agreement shall terminate on the earlier of (i) the expiration of the Lock-up Periods or (ii) the liquidation of the Company;
provided, however, that this Letter Agreement shall earlier terminate in the event that the Public Offering is not consummated
and closed by November 30, 2020; provided further that paragraph 4 of this Letter Agreement shall survive such liquidation.


 


[Signature
Pages Follow]


 






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	 	Sincerely,
	 	 	 
	 	YELLOWSTONE ACQUISITION COMPANY
	 	 	 
	 	By:	/s/
    Joshua P. Weisenburger
	 	Name:  	Joshua
    P. Weisenburger
	 	Title:	Chief
    Financial Officer


 


	BOC
    YELLOWSTONE, LLC	 
	 	 	 
	By:	/s/
    Joshua P. Weisenburger	 
	Name:  
    	Joshua
    P. Weisenburger 	 
	Title:	Chief
    Financial Officer 	 
	 	 	 
	INSIDERS:	 
	 	 	 
	By:	/s/
    Adam K. Peterson	 
	Name:
    	Adam
    K. Peterson 	 
	 	 	 
	By:	/s/
    Alex B. Rozek	 
	Name:
    	Alex
    B. Rozek 	 
	 	 	 
	By:	/s/
    Shanna Noelle Khan	 
	Name:
    	Shanna
    Noelle Khan 	 
	 	 	 
	By:	/s/
    Sydney C. Atkins	 
	Name:
    	Sydney
    C. Atkins 	 
	 	 	 
	By:	/s/
    David J. Bronczek	 
	Name:
    	David
    J. Bronczek 	 
	 	 	 
	By:	/s/
    Joshua P. Weisenburger	 
	Name:
    	Joshua
    P. Weisenburger 	 


 


[Signature
Page to Letter Agreement]