EX-10.3





 Exhibit 10.3 

INVESTMENT MANAGEMENT TRUST AGREEMENT 

This Investment Management Trust Agreement (this “Agreement”) is made effective as of October 13, 2021 by and
between Black Mountain Acquisition Corp., a Delaware corporation (the “Company”), and Continental Stock Transfer & Trust Company, a New York corporation (the “Trustee”). 

WHEREAS, the Company’s registration statement on Form S-1 (File
No. 333-259469) (the “Registration Statement”) and prospectus (the “Prospectus”) for the initial public offering of the Company’s units (the
“Units”), each of which consists of one share of the Company’s Class A common stock, par value $0.0001 per share (the “Common Stock”), and three quarters of one redeemable warrant, each whole
warrant entitling the holder thereof to purchase one share of Common Stock (such initial public offering hereinafter referred to as the “Offering”), has been declared effective as of the date hereof by the U.S. Securities and
Exchange Commission; and 
 WHEREAS, the Company has entered into an Underwriting Agreement (the “Underwriting
Agreement”) with EarlyBirdCapital, Inc. and Stephens Inc. as representatives (the “Representatives”) of the underwriters (the “Underwriters”) named therein; and 

WHEREAS, as described in the Registration Statement, $244,800,000 of the gross proceeds of the Offering and sale of the Private Placement
Warrants (as defined in the Underwriting Agreement) (or $281,520,000 if the Underwriters’ over-allotment option is exercised in full) will be delivered to the Trustee to be deposited and held in a segregated trust account located at all times
in the United States (the “Trust Account”) for the benefit of the Company and the holders of the Common Stock included in the Units issued in the Offering as hereinafter provided (the amount to be delivered to the Trustee
(and any interest subsequently earned thereon) is referred to herein as the “Property,” the stockholders for whose benefit the Trustee shall hold the Property will be referred to as the “Public
Stockholders,” and the Public Stockholders and the Company will be referred to together as the “Beneficiaries”); and 

WHEREAS, pursuant to the Underwriting Agreement, a portion of the Property equal to $8,400,000, or $9,660,000 if the Underwriters’
over-allotment option is exercised in full, is attributable to deferred underwriting discounts and commissions that may be payable by the Company to the Underwriters upon the consummation of the Business Combination (as defined below) (the
“Deferred Discount”); and 
 WHEREAS, the Company and the Trustee desire to enter into this Agreement to set forth
the terms and conditions pursuant to which the Trustee shall hold the Property. 
 NOW THEREFORE, IT IS AGREED: 

1. Agreements and Covenants of Trustee. The Trustee hereby agrees and covenants to: 

(a) Hold the Property in trust for the Beneficiaries in accordance with the terms of this Agreement in the Trust Account established by the
Trustee in the United States, maintained by the Trustee and at JPMorgan Chase Bank, N.A. (or at another U.S. chartered commercial bank with consolidated assets of $100 billion or more) and at a brokerage institution selected by the Trustee and
reasonably satisfactory to the Company; 












 (b) Manage, supervise and administer the Trust Account subject to the terms and conditions
set forth herein; 
 (c) In a timely manner, upon the written instruction of the Company, invest and reinvest the Property solely in United
States government securities within the meaning of Section 2(a)(16) of the Investment Company Act of 1940, as amended, having a maturity of 185 days or less, or in money market funds meeting the conditions of paragraphs (d)(1), (d)(2), (d)(3)
and (d)(4) of Rule 2a-7 promulgated under the Investment Company Act of 1940, as amended, which invest only in direct U.S. government treasury obligations, as determined by the Company; the Trustee may not
invest in any other securities or assets, it being understood that the Trust Account will earn no interest while account funds are uninvested awaiting the Company’s instructions hereunder and, while the account funds are invested or uninvested,
the trustee may earn bank credits or other considerations; 
 (d) Collect and receive, when due, all interest or other income arising from
the Property, which shall become part of the “Property,” as such term is used herein; 
 (e) Promptly notify the
Company of all communications received by the Trustee with respect to any Property requiring action by the Company; 
 (f) Supply any
necessary information or documents as may be requested by the Company (or its authorized agents) in connection with the Company’s preparation of the tax returns relating to assets held in the Trust Account; 

(g) Participate in any plan or proceeding for protecting or enforcing any right or interest arising from the Property if, as and when
instructed by the Company to do so; 
 (h) Render to the Company monthly written statements of the activities of, and amounts in, the Trust
Account reflecting all receipts and disbursements of the Trust Account; 
 (i) Commence liquidation of the Trust Account only after and
promptly after (x) receipt of, and only in accordance with, the terms of a letter from the Company (the “Termination Letter”) in a form substantially similar to that attached hereto as either
Exhibit A or Exhibit B, as applicable, signed on behalf of the Company by its Chief Executive Officer, President, Chief Financial Officer, Secretary or Chairman of the board of directors of the
Company (the “Board”) or other authorized officer of the Company and, in the case of Exhibit A, acknowledged and agreed to by the Representatives and complete the liquidation of the Trust Account and distribute
the Property in the Trust Account, including interest not previously released to the Company to pay its taxes (less up to $100,000 of interest that may be released to the Company to pay dissolution expenses and net of taxes payable), only as
directed in the Termination Letter and the other documents referred to therein, or (y) upon the date which is the later of (1) 18 months after the closing of the Offering and (2) such later date as may be approved by the Company’s
stockholders in accordance with the Company’s amended and restated certificate of incorporation (the “Charter”), if a Termination Letter has not been received by the Trustee prior to such date, in which case the Trust
Account shall be liquidated in accordance with the procedures set forth in the Termination Letter attached as Exhibit B and the Property in the Trust Account, including interest not previously released to the Company to pay
its taxes (less up to $100,000 of interest that may be released to the Company to pay dissolution expenses and net of taxes payable) shall be distributed to the Public Stockholders of record as of such date; 

  
 2 













 (j) Upon written request from the Company, which may be given from time to time in a form
substantially similar to that attached hereto as Exhibit C (a “Tax Payment Withdrawal Instruction”), withdraw from the Trust Account and distribute to the Company the amount of interest earned on the
Property requested by the Company to cover any income or franchise tax obligation owed by the Company as a result of assets of the Company or interest or other income earned on the Property, which amount shall be delivered directly to the Company by
electronic funds transfer or other method of prompt payment, and the Company shall forward such payment to the relevant taxing authority, so long as there is no reduction in the principal amount per share initially deposited in the Trust Account;
provided, however, that to the extent there is not sufficient cash in the Trust Account to pay such tax obligation, the Trustee shall liquidate such assets held in the Trust Account as shall be designated by the Company in writing to
make such distribution; provided, further, that if the tax to be paid is a franchise tax, the written request by the Company to make such distribution shall be accompanied by a copy of the franchise tax bill from the State of Delaware
for the Company and a written statement from the principal financial officer of the Company setting forth the actual amount payable. The written request of the Company referenced above shall constitute presumptive evidence that the Company is
entitled to said funds, and the Trustee shall have no responsibility to look beyond said request; 
 (k) Upon written request from the
Company, which may be given from time to time in a form substantially similar to that attached hereto as Exhibit D (a “Stockholder Redemption Withdrawal Instruction”), the Trustee shall distribute on
behalf of the Company the amount requested by the Company to be used to redeem shares of Common Stock from Public Stockholders properly submitted in connection with a stockholder vote to approve an amendment to the Company’s Charter that would
affect the substance or timing of the Company’s obligation to redeem 100% of its public shares of Common Stock if the Company has not consummated an initial Business Combination within such time as is described in the Company’s Charter.
The written request of the Company referenced above shall constitute presumptive evidence that the Company is entitled to distribute said funds, and the Trustee shall have no responsibility to look beyond said request; and 

(l) Not make any withdrawals or distributions from the Trust Account other than pursuant to Sections 1(i),
1(j) or 1(k) above. 
 2. Agreements and Covenants of the Company. The Company hereby agrees and covenants to: 

(a) Give all instructions to the Trustee hereunder in writing, signed by the Company’s Chairperson of the Board, President, Chief
Executive Officer, Chief Financial Officer or Secretary. 

  
 3 













 In addition, except with respect to its duties under Sections 1(i), 1(j) and
1(k) hereof, the Trustee shall be entitled to rely on, and shall be protected in relying on, any verbal or telephonic advice or instruction which it, in good faith and with reasonable care, believes to be given by any one of the persons
authorized above to give written instructions, provided that the Company shall promptly confirm such instructions in writing; 
 (b)
Subject to Section 4 hereof, hold the Trustee harmless and indemnify the Trustee from and against any and all expenses, including reasonable counsel fees and disbursements, or losses suffered by the Trustee in connection
with any action taken by it hereunder and in connection with any action, suit or other proceeding brought against the Trustee involving any claim, or in connection with any claim or demand, which in any way arises out of or relates to this
Agreement, the services of the Trustee hereunder, or the Property or any interest earned on the Property, except for expenses and losses resulting from the Trustee’s gross negligence, fraud or willful misconduct. Promptly after the receipt by
the Trustee of notice of demand or claim or the commencement of any action, suit or proceeding, pursuant to which the Trustee intends to seek indemnification under this Section 2(b), it shall notify the Company in writing
of such claim (an “Indemnified Claim”). The Trustee shall have the right to conduct and manage the defense against such Indemnified Claim; provided that the Trustee shall obtain the consent of the Company with respect
to the selection of counsel, which consent shall not be unreasonably withheld. The Trustee may not agree to settle any Indemnified Claim without the prior written consent of the Company, which such consent shall not be unreasonably withheld. The
Company may participate in such action with its own counsel; 
 (c) Pay the Trustee the fees set forth on Schedule A hereto, including
an initial acceptance fee, annual administration fee, and transaction processing fee which fees shall be subject to modification by the parties from time to time. It is expressly understood that the Property shall not be used to pay such fees unless
and until it is distributed to the Company pursuant to Sections 1(i), 1(j) or 1(k) hereof. The Company shall pay the Trustee the initial acceptance fee and the first annual administration fee at the
consummation of the Offering. The Company shall not be responsible for any other fees or charges of the Trustee except as set forth in this Section 2(c), Schedule A and as may be provided in
Section 2(b) hereof; 
 (d) In connection with any vote of the Company’s stockholders regarding a merger,
capital stock exchange, asset acquisition, stock purchase, reorganization or similar business combination involving the Company and one or more businesses (the “Business Combination”), provide to the Trustee an affidavit or
certificate of the inspector of elections for the stockholder meeting verifying the vote of such stockholders regarding such Business Combination; 

(e) Provide the Representatives with a copy of any Termination Letter(s) and/or any other correspondence that is sent to the Trustee with
respect to any proposed withdrawal from the Trust Account promptly after it issues the same; 
 (f) Instruct the Trustee to make only those
distributions that are permitted under this Agreement, and refrain from instructing the Trustee to make any distributions that are not permitted under this Agreement; and 

(g) Within four (4) business days after the Underwriters exercise the over-allotment option (or any unexercised portion thereof) or such
over-allotment option expires, provide the Trustee with a notice in writing of the total amount of the Deferred Discount, which shall in no event be less than $8,400,000. 

  
 4 













 3. Limitations of Liability. The Trustee shall have no responsibility or liability
to: 
 (a) Imply obligations, perform duties, inquire or otherwise be subject to the provisions of any agreement or document other than this
Agreement and that which is expressly set forth herein; 
 (b) Take any action with respect to the Property, other than as directed in
Section 1 hereof, and the Trustee shall have no liability to any party except for liability arising out of the Trustee’s gross negligence, fraud or willful misconduct; 

(c) Institute any proceeding for the collection of any principal and income arising from, or institute, appear in or defend any proceeding of
any kind with respect to, any of the Property unless and until it shall have received instructions from the Company given as provided herein to do so and the Company shall have advanced or guaranteed to it funds sufficient to pay any expenses
incident thereto; 
 (d) Refund any depreciation in principal of any Property; 

(e) Assume that the authority of any person designated by the Company to give instructions hereunder shall not be continuing unless provided
otherwise in such designation, or unless the Company shall have delivered a written revocation of such authority to the Trustee; 
 (f) The
other parties hereto or to anyone else for any action taken or omitted by it, or any action suffered by it to be taken or omitted, in good faith and in the Trustee’s best judgment, except for the Trustee’s gross negligence, fraud or
willful misconduct. The Trustee may rely conclusively and shall be protected in acting upon any order, notice, demand, certificate, opinion or advice of counsel (including counsel chosen by the Trustee, which counsel may be the Company’s
counsel), statement, instrument, report or other paper or document (not only as to its due execution and the validity and effectiveness of its provisions, but also as to the truth and acceptability of any information therein contained) which the
Trustee believes, in good faith and with reasonable care, to be genuine and to be signed or presented by the proper person or persons. The Trustee shall not be bound by any notice or demand, or any waiver, modification, termination or rescission of
this Agreement or any of the terms hereof, unless evidenced by a written instrument delivered to the Trustee, signed by the proper party or parties and, if the duties or rights of the Trustee are affected, unless it shall give its prior written
consent thereto; 
 (g) Verify the accuracy of the information contained in the Registration Statement; 

(h) Provide any assurance that any Business Combination entered into by the Company or any other action taken by the Company is as contemplated
by the Registration Statement; 
 (i) File information returns with respect to the Trust Account with any local, state or federal taxing
authority or provide periodic written statements to the Company documenting the taxes payable by the Company, if any, relating to any interest income earned on the Property; 

  
 5 













 (j) Prepare, execute and file tax reports, income or other tax returns and pay any taxes
with respect to any income generated by, and activities relating to, the Trust Account, regardless of whether such tax is payable by the Trust Account or the Company, including, but not limited to, income tax obligations, except pursuant to
Section 1(j) hereof; or 
 (k) Verify calculations, qualify or otherwise approve the Company’s written
requests for distributions pursuant to Sections 1(i), 1(j) and 1(k) hereof. 
 4. Trust Account
Waiver. The Trustee has no right of set-off or any right, title, interest or claim of any kind (a “Claim”) to, or to any monies in, the Trust Account, and hereby irrevocably waives
any Claim to, or to any monies in, the Trust Account that it may have now or in the future. In the event the Trustee has any Claim against the Company under this Agreement, including, without limitation, under Section 2(b)
or Section 2(c) hereof, the Trustee shall pursue such Claim solely against the Company and its assets outside the Trust Account and not against the Property or any monies in the Trust Account. 

5. Termination. This Agreement shall terminate as follows: 

(a) If the Trustee gives written notice to the Company that it desires to resign under this Agreement, the Company shall use its reasonable
efforts to locate a successor trustee, pending which the Trustee shall continue to act in accordance with this Agreement. At such time that the Company notifies the Trustee that a successor trustee has been appointed and has agreed to become subject
to the terms of this Agreement, the Trustee shall transfer the management of the Trust Account to the successor trustee, including but not limited to the transfer of copies of the reports and statements relating to the Trust Account, whereupon this
Agreement shall terminate; provided, however, that in the event that the Company does not locate a successor trustee within ninety (90) days of receipt of the resignation notice from the Trustee, the Trustee may submit an
application to have the Property deposited with any court in the State of New York or with the United States District Court for the Southern District of New York and upon such deposit, the Trustee shall be immune from any liability whatsoever; or

 (b) At such time that the Trustee has completed the liquidation of the Trust Account and its obligations in accordance with the provisions
of Section 1(i) hereof and distributed the Property in accordance with the provisions of the Termination Letter, this Agreement shall terminate except with respect to Section 2(b) hereof. 

6. Miscellaneous. 
 (a)
The Company and the Trustee each acknowledge that the Trustee will follow the security procedures set forth below with respect to funds transferred from the Trust Account. The Company and the Trustee will each restrict access to confidential
information relating to such security procedures to authorized persons. Each party must notify the other party immediately if it has reason to believe unauthorized persons may have obtained access to such confidential information, or of any change
in its authorized personnel. In executing funds transfers, the Trustee shall rely upon all information supplied to it by the Company, including, account names, account numbers, and all other identifying information relating to a Beneficiary,
Beneficiary’s bank or intermediary bank. Except for any liability arising out of the Trustee’s gross negligence, fraud or willful misconduct, the Trustee shall not be liable for any loss, liability or expense resulting from any error in
the information or transmission of the funds. 

  
 6 













 (b) This Agreement shall be governed by and construed and enforced in accordance with the
laws of the State of New York, without giving effect to conflicts of law principles that would result in the application of the substantive laws of another jurisdiction. This Agreement may be executed in several original or facsimile counterparts,
each one of which shall constitute an original, and together shall constitute but one instrument. 
 (c) This Agreement contains the entire
agreement and understanding of the parties hereto with respect to the subject matter hereof. Except for Sections 1(i), 1(j) and 1(k) hereof (which sections may not be modified, amended or deleted without the affirmative vote of
sixty-five percent (65%) of the then outstanding shares of Common Stock and shares of Class B common stock, par value $0.0001 per share, of the Company, voting together as a single class; provided that no such amendment will affect any Public
Stockholder who has properly elected to redeem his, her or its shares of Common Stock in connection with a stockholder vote to approve an amendment to this Agreement that would affect the substance or timing of the Company’s obligation to
redeem 100% of its public shares of Common Stock if the Company does not complete its initial Business Combination within the time frame specified in the Company’s Charter), this Agreement or any provision hereof may only be changed, amended or
modified (other than to correct a typographical error) by a writing signed by each of the parties hereto. 
 (d) The parties hereto consent
to the jurisdiction and venue of any state or federal court located in the City of New York, State of New York, for purposes of resolving any disputes hereunder. AS TO ANY CLAIM, CROSS-CLAIM OR COUNTERCLAIM IN ANY WAY RELATING TO THIS AGREEMENT,
EACH PARTY WAIVES THE RIGHT TO TRIAL BY JURY. 
 (e) Any notice, consent or request to be given in connection with any of the terms or
provisions of this 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 by facsimile or email transmission: 

if to the Trustee, to: 

Continental Stock Transfer & Trust Company 

1 State Street, 30th Floor 
 New
York, New York 10004 
 Attn: Francis Wolf and Celeste Gonzalez 

Email: fwolf@continentalstock.com 

Email: cgonzalez@continentalstock.com 

  
 7 













 if to the Company, to: 

Black Mountain Acquisition Corp. 

425 Houston Street, Suite 400 Fort Worth, Texas 76102 

Attn: Rhett Bennett 
 Email:
rhett.bennett@blackmtn.com 
 in each case, with copies to: 

Vinson & Elkins L.L.P. 

1001 Fannin Street, Suite 2500 

Houston, Texas 77002 
 Attn: Ramey
Layne 
 Email: rlayne@velaw.com 

and 
 EarlyBirdCapital, Inc. 

366 Madison Avenue, 8th Floor 

New York, New York 10017 
 Attn:
Mike Powell 
 Email: Mpowell@ebcap.com

and 
 Stephens Inc. 

300 Crescent Court Suite 600 

Dallas, Texas 75201 
 Attn: Keith
J. Behrens 
 Email: keith.behrens@stephens.com 

and 
 Graubard Miller 

The Chrysler Building 
 405
Lexington Avenue 
 New York, NY 10174 

Attn: David Alan Miller 
 Email:
DMiller@graubard.com 
 (f) Each of the Company and the Trustee hereby represents that it has the full right and power and has been duly
authorized to enter into this Agreement and to perform its respective obligations as contemplated hereunder. The Trustee acknowledges and agrees that it shall not make any claims or proceed against the Trust Account, including by way of set-off, and shall not be entitled to any funds in the Trust Account under any circumstance. 
 (g) Each of
the Company and the Trustee hereby acknowledges and agrees that each of the Representatives, on behalf of the Underwriters, is a third party beneficiary of this Agreement. 

  
 8 













 (h) Except as specified herein, no party to this Agreement may assign its rights or delegate
its obligations hereunder to any other person or entity. 
 [Signature Page Follows] 

  
 9 













 IN WITNESS WHEREOF, the parties have duly executed this Investment Management Trust
Agreement as of the date first written above. 
  

			
	Continental Stock Transfer & Trust Company, as Trustee
		
	By:	 	 /s/ Francis Wolf

	Name: Francis Wolf
	Title: Vice President
	
	Black Mountain Acquisition Corp.
		
	By:	 	 /s/ Rhett Bennett

	Name: Rhett Bennett
	Title: Chief Executive Officer


 [Signature Page to Investment Management Trust Agreement] 












 SCHEDULE A 
  

							
	 Fee Item
	  	 Time and method of payment
	  	Amount	 
	 Initial set-up fee
	  	Initial closing of Offering by wire transfer	  	$	3,500.00	 
	 Trustee administration fee
	  	Payable annually. First year fee payable at initial closing of Offering by wire transfer; thereafter, payable by wire transfer or check.	  	$	10,000.00	 
	 Transaction processing fee for disbursements to Company under Sections 1(i),
1(j) and 1(k)
	  	Deduction by Trustee from accumulated income following disbursement made to Company under Section 1	  	$	250.00	 
	 Paying agent service fees for disbursement to Public Stockholders under Sections 1(i)
and 1(k)
	  	Billed to Company upon delivery of service pursuant to Section 1(i) and 1(k)	  	 	Prevailing rates	 













 EXHIBIT A 

[Letterhead of Company] 

[Insert date] 
 Continental Stock
Transfer & Trust Company 
 1 State Street, 30th Floor 

New York, New York 10004 
 Attn: Francis Wolf and Celeste Gonzalez

 Re: Trust Account -Termination Letter 

Dear Mr. Wolf and Ms. Gonzalez: 

Pursuant to Section 1(i) of the Investment Management Trust Agreement between Black Mountain Acquisition (the
“Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of [         ], 2021 (the “Trust
Agreement”), this is to advise you that the Company has entered into an agreement with [         ] (the “Target Business”) to consummate a business combination with the
Target Business (the “Business Combination”) on or about [         ], 20[     ]. The Company shall notify you at least
seventy-two (72) hours in advance of the actual date of the consummation of the Business Combination (the “Consummation Date”). Capitalized terms used but not defined herein shall
have the meanings set forth in the Trust Agreement. 
 In accordance with the terms of the Trust Agreement, we hereby authorize you to
commence to liquidate all of the assets of the Trust Account and to transfer the proceeds into the trust operating account at JPMorgan Chase Bank, N.A. to the effect that, on the Consummation Date, all of the funds held in the Trust Account will be
immediately available for transfer to the account or accounts that the Company shall direct on the Consummation Date (including as directed to it by the Representatives on behalf of the Underwriters (with respect to the Deferred Discount)). It is
acknowledged and agreed that while the funds are on deposit in the trust operating account at JPMorgan Chase Bank, N.A. awaiting distribution, the Company will not earn any interest or dividends. 

On the Consummation Date (i) counsel for the Company shall deliver to you written notification that the Business Combination has been
consummated, or will be consummated concurrently with your transfer of funds to the accounts as directed by the Company (the “Notification”) and (ii) the Company shall deliver to you (a) a certificate of the Chief
Executive Officer of the Company, which verifies that the Business Combination has been approved by a vote of the Company’s stockholders, if a vote is held and (b) a joint written instruction signed by the Company and the Representatives
with respect to the transfer of the funds held in the Trust Account, including payment of amounts owed to public stockholders who have properly exercised their redemption rights and payment of the Deferred Discount directly to the account or
accounts directed by the Representatives from the Trust Account (the “Instruction Letter”). You are hereby directed and authorized to transfer the funds held in the Trust Account immediately upon your receipt of the
Notification and the Instruction Letter, in accordance with the terms of the Instruction Letter. In the event that certain deposits held in the Trust Account may not be liquidated by the 

  
 A-1 













 
Consummation Date without penalty, you will notify the Company in writing of the same and the Company shall direct you as to whether such funds should remain in the Trust Account and be
distributed after the Consummation Date to the Company. Upon the distribution of all the funds, net of any payments necessary for reasonable unreimbursed expenses related to liquidating the Trust Account, your obligations under the Trust Agreement
shall be terminated. 
 In the event that the Business Combination is not consummated on the Consummation Date described in the notice
thereof and we have not notified you on or before the original Consummation Date of a new Consummation Date, then upon receipt by the Trustee of written instructions from the Company, the funds held in the Trust Account shall be reinvested as
provided in Section 1(c) of the Trust Agreement on the business day immediately following the Consummation Date as set forth in such written instructions as soon thereafter as possible. 

 

			
	Very truly yours,
	
	Black Mountain Acquisition Corp.
		
	By:	 	  

	Name:	 	
	Title:	 	


 Agreed and acknowledged by: 

EarlyBirdCapital, Inc. 
  

			
	By:	 	  

	Name:	 	
	Title:	 	
	
	Stephens Inc.
		
	By:	 	  

	Name:	 	
	Title:	 	


  
 A-2 













 EXHIBIT B 

[Letterhead of Company] 

[Insert date] 
 Continental Stock
Transfer & Trust Company 
 1 State Street, 30th Floor 

New York, New York 10004 
 Attn: Francis Wolf and Celeste Gonzalez

 Re: Trust Account—Termination Letter 

Dear Mr. Wolf and Ms. Gonzalez: 

Pursuant to Section 1(i) of the Investment Management Trust Agreement between Black Mountain Acquisition Corp. (the
“Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of [ ], 2021 (the “Trust Agreement”), this is to advise you that the Company has
been unable to effect a business combination with a target business within the time frame specified in the Company’s Amended and Restated Certificate of Incorporation (the “Charter”), as described in the Company’s
Prospectus relating to the Offering. Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement. 

In accordance with the terms of the Trust Agreement, we hereby authorize you to liquidate all of the assets in the Trust Account and to
transfer the total proceeds into the trust operating account at JPMorgan Chase Bank, N.A. to await distribution to the Public Stockholders. The Company has selected [ ], 20[ ] as the effective date for the purpose of determining when the Public
Stockholders will be entitled to receive their share of the liquidation proceeds. You agree to be the paying agent of record and, in your separate capacity as paying agent, agree to distribute said funds directly to the Public Stockholders in
accordance with the terms of the Trust Agreement and the Company’s Charter. Upon the distribution of all the funds, net of any payments necessary for reasonable unreimbursed expenses related to liquidating the Trust Account, your obligations
under the Trust Agreement shall be terminated, except to the extent otherwise provided in Section 1(j) of the Trust Agreement. 
  

			
	Very truly yours,
	
	Black Mountain Acquisition Corp.
		
	By:	 	  

	Name:	 	
	Title:	 	


  

			
	cc:	 	EarlyBirdCapital, Inc.
		 	Stephens Inc.


  
 B-1 













 EXHIBIT C 

[Letterhead of Company] 

[Insert date] 
 Continental Stock
Transfer & Trust Company 
 1 State Street, 30th Floor 

New York, New York 10004 
 Attn: Francis Wolf and Celeste Gonzalez

 Re: Trust Account—Tax Payment Withdrawal Instruction 

Dear Mr. Wolf and Ms. Gonzalez: 

Pursuant to Section 1(j) of the Investment Management Trust Agreement between Black Mountain Acquisition Corp. (the
“Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of [ ], 2021 (the “Trust Agreement”), the Company hereby requests that you deliver
to the Company $[ ] of the interest income earned on the Property as of the date hereof. Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement. 

The Company needs such funds to pay for the tax obligations as set forth on the attached tax return or tax statement. In accordance with the
terms of the Trust Agreement, you are hereby directed and authorized to transfer (via wire transfer) such funds promptly upon your receipt of this letter to the Company’s operating account at: 

[WIRE INSTRUCTION INFORMATION] 
  

			
	Very truly yours,
	
	Black Mountain Acquisition Corp.
		
	By:	 	  

	Name:	 	
	Title:	 	


  

			
	cc:	 	EarlyBirdCapital, Inc.
		 	Stephens Inc.


  
 C-1 













 EXHIBIT D 

[Letterhead of Company] 

[Insert date] 
 Continental Stock
Transfer & Trust Company 
 1 State Street, 30th Floor 

New York, New York 10004 
 Attn: Francis Wolf and Celeste Gonzalez

 Re: Trust Account—Stockholder Redemption Withdrawal Instruction 

Dear Mr. Wolf and Ms. Gonzalez: 

Pursuant to Section 1(k) of the Investment Management Trust Agreement between Black Mountain Acquisition Corp. (the
“Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of [ ], 2021 (the “Trust Agreement”), the Company hereby requests that you deliver
to the redeeming Public Stockholders of the Company $[ ] of the principal and interest income earned on the Property as of the date hereof. Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement. 

The Company needs such funds to pay its Public Stockholders who have properly elected to have their shares of Common Stock redeemed by the
Company in connection with a stockholder vote to approve an amendment to the Company’s amended and restated certificate of incorporation (the “Charter”) that affects the substance or timing of the Company’s
obligation to redeem 100% of its public shares of Common Stock if the Company has not consummated an initial Business Combination within such time as is described in the Company’s Charter. As such, you are hereby directed and authorized to
transfer (via wire transfer) such funds promptly upon your receipt of this letter to the redeeming Public Stockholders in accordance with your customary procedures. 

 

			
	Very truly yours,
	
	Black Mountain Acquisition Corp.
		
	By:	 	  

	Name:	 	
	Title:	 	


  

			
	cc:	 	EarlyBirdCapital, Inc.
		 	Stephens Inc.


  
 D-1