Sec Form 3 Filing - Platinum Equity Capital Partners V, L.P. @ Custom Truck One Source, Inc. - 2020-12-03

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Platinum Equity Capital Partners V, L.P. 2. Issuer Name and Ticker or Trading Symbol Custom Truck One Source, Inc. [ NSCO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O PLATINUM EQUITY ADVISORS, LLC, 360 NORTH CRESCENT DRIVE, SOUTH BUILDING 3. Date of Earliest Transaction (MM/DD/YY) 12/03/2020 (Street) BEVERLY HILLS, CA90210 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, par value $0.0001 per share 34,298,418 ( 1 ) ( 2 ) ( 3 ) ( 4 ) ( 5 ) ( 6 ) I ( 1 ) ( 2 ) ( 3 ) ( 4 ) ( 5 ) ( 6 ) See Footnotes ( 1 ) ( 2 ) ( 3 ) ( 4 ) ( 5 ) ( 6 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Platinum Equity Capital Partners V, L.P. C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA90210 X Platinum Equity Partners V, L.P. C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA09210 X Platinum Equity Partners V, LLC C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA09210 X Platinum Equity Investment Holdings V, LLC C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA09210 X Platinum Equity Investment Holdings V Manager, LLC C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA09210 X Platinum Equity InvestCo, L.P. C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA90210 X Platinum InvestCo (Cayman), LLC C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA90210 X Platinum Equity Investment Holdings IC (Cayman), LLC C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA90210 X Platinum Equity Investment Holdings, LLC C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA90210 X PE One Source Holdings, LLC C/O PLATINUM EQUITY ADVISORS, LLC 360 NORTH CRESCENT DRIVE, SOUTH BUILDING BEVERLY HILLS, CA09210 X Signatures See Exhibit 99.2 Signatures 04/02/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Two Forms 3 are being filed, covering a total of twelve (12) persons listed in this footnote. This is the first of the two Forms 3 (the "First Form 3") and is being filed by each of: (i) Platinum Equity Capital Partners V, L.P., a Delaware limited partnership ("PECP V"), (ii) Platinum Equity Partners V, L.P., a Delaware limited partnership ("PEP V LP"), (iii) Platinum Equity Partners V, LLC, a Delaware limited liability company ("PEP V LLC"), (iv) Platinum Equity Investment Holdings V, LLC, a Delaware limited liability company ("PEIH V"), (v) Platinum Equity Investment Holdings V Manager, LLC, a Delaware limited liability company ("PEIH V Manager"), (vi) Platinum Equity InvestCo, L.P., a Cayman Islands limited partnership ("PEIC LP"), (vii) Platinum InvestCo (Cayman), LLC, a Cayman Islands limited liability company ("PIC LLC"), (viii) Platinum Equity Investment Holdings IC (Cayman), LLC, a Delaware limited liability company ("PEIH IC LLC") (To be continue on Footnote 2, 3 and 4) ( 2 )(ix) Platinum Equity Investment Holdings, LLC, a Delaware limited liability company ("Platinum Holdings") and (x) PE One Source Holdings, LLC, a Delaware limited liability company ("PE One Source"). The second of the two Forms 3 (the "Second Form 3") is being filed by (xi) Platinum Equity, LLC, a Delaware limited liability company ("Platinum Equity"), and (xii) Tom Gores, an individual and citizen of the United States (each person or entity listed in clauses (i)-(xii), a "Reporting Person" and, collectively, the "Reporting Persons"). PECP V holds a majority of the outstanding equity in PE One Source and, accordingly, may be deemed to beneficially own the shares of common stock, par value $0.0001 per share (the "Shares ") of Nesco Holdings, Inc. (the "Issuer") beneficially owned by PE One Source. PEP V LP is the general partner of PECP V and, accordingly, may be deemed to beneficially own the Shares beneficially owned by PECP V. ( 3 )PEP V LLC is the general partner of PEP V LP and, accordingly, may be deemed to beneficially own the Shares beneficially owned by PEP V LP. PEIH V holds all of the outstanding equity in PEP V LLC and, accordingly, may be deemed to beneficially own the Shares beneficially owned by PEP V LLC. PEIH V Manager is the sole manager of PEIH V and, accordingly, may be deemed to beneficially own the Shares beneficially owned by PEIH V. PEIC LP holds all of the outstanding equity in PEIH V and, accordingly, may be deemed to beneficially own the Shares beneficially owned by PEIH V. PIC LLC holds a controlling interest in PEIC LP and, accordingly, may be deemed to beneficially own the Shares beneficially owned by PEIC LP. PEIH IC LLC is the general partner of PEIC LP and, accordingly, may be deemed to beneficially own the Shares beneficially owned by PEIC LP. ( 4 )Platinum Holdings is the sole member of PEIH IC LLC and, accordingly, may be deemed to beneficially own the Shares beneficially owned by PEIH IC LLC. Platinum Equity is the sole member of Platinum Holdings, and PEIH V Manager and, accordingly, may be deemed to beneficially own the Shares beneficially owned by each of Platinum Holdings and PEIH V Manager. Platinum Equity and Tom Gores, together, hold a controlling interest in PIC LLC and may be deemed to beneficially own the Shares beneficially owned by PIC LLC. Tom Gores is the Chairman and Chief Executive Officer of Platinum Equity and, accordingly, may be deemed to beneficially own the Shares beneficially owned by Platinum Equity. Mr. Gores disclaims beneficial ownership of all the Shares held by each of the entities listed above with respect to which he does not have a pecuniary interest. Because of the relationship discussed above, each Reporting Person may be deemed to beneficially own the Shares reported in this Form 3. ( 5 )On December 3, 2020, certain affiliates of Energy Capital Partners ("ECP"), and Capitol Acquisition Management IV, LLC and Capitol Acquisition Founder IV, LLC (together, "Capitol" and together with ECP, the "Supporting Stockholders"), entered into a Voting and Support Agreement (the "Voting Agreement") with PE One Source. The Voting Agreement was entered into in connection with the Common Stock Purchase Agreement (the "Investment Agreement"), dated as of December 3, 2020, by and between the Issuer and PE One Source. For additional information regarding the Voting Agreement and the Investment Agreement, see Schedule 13D filed by the Reporting Persons with the Securities and Exchange Commission on December 11, 2020 (the "Schedule 13D"). ( 6 )As a result of certain provisions contained in the Voting Agreement, the Reporting Persons may be deemed to have shared power to vote, and beneficial ownership of, up to an aggregate of 34,298,418 Shares with respect to the matters covered by the Voting Agreement, representing approximately 69.8% of the 49,156,753 Shares outstanding as of December 1, 2020 (as represented to the Reporting Persons by the Issuer pursuant to the Investment Agreement), pursuant to Rule 13d-3 under the Securities Exchange Act of 1934, as amended. Notwithstanding the preceding sentence, the Reporting Persons hereby disclaim beneficial ownership of all such Shares that are the subject of the Voting Agreement and this Form 3 shall not be construed as an admission that the Reporting Persons are, for any or all purposes, the beneficial owners of any such Shares that are the subject of the Voting Agreement and covered by this Form 3.

Remarks: Exhibit 24.1 - Power of Attorney (Mr. Gores), incorporated herein by reference to Exhibit 4 to the Schedule 13D; Exhibit 99.1 - Joint Filing Agreement, incorporated herein by reference to Exhibit 3 to the Schedule 13D; and Exhibit 99.2 - Signatures Form.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.