Sec Form 3 Filing - BC Partners Holdings Ltd @ Cyxtera Technologies, Inc. - 2021-07-29

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

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1. Name and Address of Reporting Person BC Partners Holdings Ltd 2. Issuer Name and Ticker or Trading Symbol Cyxtera Technologies, Inc. [ CYXT] 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) WEST WING, FLOOR 2, TRAFALGAR, COURT, LES BANQUES 3. Date of Earliest Transaction (MM/DD/YY) 07/29/2021 (Street) ST. PETER PORT, GUERNSEY, GY1 4LY 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 Class A Common Stock 106,100,000 ( 1 ) I By SIS Holdings LP ( 2 ) ( 3 )

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 BC Partners Holdings Ltd WEST WING, FLOOR 2, TRAFALGAR COURT, LES BANQUES ST. PETER PORT, GUERNSEYGY1 4LY X BC Partners Group Holdings Ltd WEST WING, FLOOR 2, TRAFALGAR COURT, LES BANQUES ST. PETER PORT, GUERNSEYGY1 4LY X BCEC - Cyxtera Technologies Holdings (Guernsey) L.P. ARNOLD HOUSE PO BOX 273 ST JULIAN'S AVENUE ST PETER, PORT GUERNESEYGY1 3RD X BCEC Management X Ltd ARNOLD HOUSE PO BOX 273 ST JULIAN'S AVENUE, ST PETER, PORT GUERNESEY GY1 3RD X SIS Holdings LP 2333 PONCE DE LEON BLVD, STE 900 CORAL GABLES, FL33134 X SIS Holdings GP LLC 2333 PONCE DE LEON BLVD, STE 900 CORAL GABLES, FL33134 X Medina Capital Fund II - SIS Holdco, LP 2333 PONCE DE LEON BOULEVARD, STE 900 CORAL GABLES, FL33134 X Signatures BC Partners Holdings Limited, By: /s/ Mark Rodliffe, Name: Mark Rodliffe, Title: Director 08/09/2021 Signature of Reporting Person Date BC Partners Group Holdings Limited, By: /s/ Mark Rodliffe, Name: Mark Rodliffe, Title: Director 08/09/2021 Signature of Reporting Person Date BCEC-Cyxtera Technologies Holdings (Guernsey) L.P., By: /s/ Mark Rodliffe, Name: Mark Rodliffe, Title: Director 08/09/2021 Signature of Reporting Person Date BCEC Management X Limited, By: /s/ Mark Rodliffe, Name: Mark Rodliffe, Title: Director 08/09/2021 Signature of Reporting Person Date SIS Holdings LP, By: SIS Holdings GP, LLC, its General Partner, By: /s/ Manuel D. Medina, Name: Manuel D. Medina, Title: Chief Executive Officer 08/09/2021 Signature of Reporting Person Date SIS Holdings GP LLC, By: /s/ Manuel D. Medina, Name: Manuel D. Medina, Title: Chief Executive Officer 08/09/2021 Signature of Reporting Person Date Medina Capital Fund II - SIS Holdco, L.P., By: /s/ Manuel D. Medina, Name: Manuel D. Medina, Title: Authorized Signatory 08/09/2021 Signature of Reporting Person Date Medina Capital Fund II - SIS Holdco GP, LLC, By: /s/ Manuel D. Medina, Name: Manuel D. Medina, Title: Authorized Signatory 08/09/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Pursuant to the business combination of Starboard Value Acquisition Corp. and Cyxtera Technologies, Inc. ("Legacy Cyxtera"), all of the outstanding common stock of Legacy Cyxtera, which was held 100% by SIS Holdings LP, was converted into the right to receive 106,100,000 shares of Class A common stock of the Issuer. ( 2 )The general partner of SIS Holdings LP is SIS Holdings GP, LLC ("SIS GP"). SIS GP is managed by a board of directors, a majority of which is appointed by BCEC Cyxtera Technologies Holdings (Guernsey) L.P. (the "BC Stockholder"). The general partners of the BC Stockholder are CIE Management IX Limited and BCEC Management X Limited, which are controlled by the board of directors, which are appointed by BC Partners Group Holdings Limited, which is a majority-owned subsidiary of BC Partners Holdings Limited, which is controlled by Lee Clark, Karen Jamieson, Mark Rodliffe and Nikos Stathopoulos. As a result, each of the foregoing entities may be deemed to share voting and investment power over the shares held directly by SIS Holdings LP, but disclaim beneficial ownership of the securities reported herein except to the extent of their pecuniary interest therein. ( 3 )Pursuant to a Stockholder Matters Agreement, dated as of July 30, 2021, Medina Capital Fund II- SIS Holdco, L.P. (the "Medina Stockholder") maintains a negative consent right over the disposition of the securities held by SIS Holdings LP. Medina Capital Fund II - SIS Holdco GP, LLC ("Medina GP") is the general partner of the Medina Stockholder. Manuel D. Medina ultimately controls Medina GP. As such, the each of the Medina Stockholder, Medina GP and Mr. Medina may be deemed to share beneficial ownership over the securities held directly by SIS Holdings LP. Each of Mr. Medina and the foregoing entities disclaim beneficial ownership of the securities reported herein except to the extent of their pecuniary interest therein.

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).

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