Statement of Changes in Beneficial Ownership (4)

FORM 4 [X] 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 OF SECURITIES
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* CRP IV AIV GP, L.L.C.	2. Issuer Name and Ticker or Trading Symbol CoreSite Realty Corp [ COR ]	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 THE CARLYLE GROUP, 1001, PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH	3. Date of Earliest Transaction (MM/DD/YYYY) 8/5/2020
(Street) WASHINGTON, DC 20004-2505 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) ___ Form filed by One Reporting Person _ X _ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	8/5/2020		M		230172	A	⁽¹⁾	230172	I	See footnote ⁽²⁾
Common Stock	8/5/2020		S		230172	D	$128.55	0	I	See footnote ⁽²⁾

*Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)*
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		7. Title and Amount of Securities Underlying Derivative Security (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)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)
Operating Partnership Units	⁽¹⁾	8/5/2020		M			230172	⁽¹⁾	⁽¹⁾	Common Stock	230172	⁽¹⁾	0	I	See footnote ⁽²⁾

Explanation of Responses:
(1)	The operating partnership units are redeemable at any time for cash or, at the election of the Issuer, exchangeable for shares of common stock on a one-for-one basis, and have no expiration date.
(2)	Carlyle Realty III GP, L.L.C. is the general partner of Carlyle Realty III, L.P., which is the manager of CoreSite CRP III Holdings, LLC. CRP III AIV GP, L.L.C. is the general partner of CRP III AIV GP, L.P., which is the general partner of CRQP III AIV, L.P., which is the sole member of CoreSite CRP III Holdings (VCOC), LLC. Carlyle Realty IV GP, L.L.C. is the general partner of Carlyle Realty IV, L.P., which is the manager of CoreSite CRP IV Holdings, LLC. CRP IV AIV GP, L.L.C. is the general partner of CRP IV AIV GP, L.P., which is the general partner of each of CRP IV-A AIV, L.P. and CRQP IV AIV, L.P., which are the managing members of CoreSite CRP IV Holdings (VCOC I), LLC and CoreSite CRP IV Holdings (VCOC II), LLC, respectively.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
CRP IV AIV GP, L.L.C. C/O THE CARLYLE GROUP, 1001 PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH WASHINGTON, DC 20004-2505		X
CRP IV AIV GP, L.P. C/O THE CARLYLE GROUP, 1001 PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH WASHINGTON, DC 20004-2505		X
CRP IV-A AIV, L.P. C/O THE CARLYLE GROUP, 1001 PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH WASHINGTON, DC 20004-2505		X
CRQP IV AIV, L.P. C/O THE CARLYLE GROUP, 1001 PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH WASHINGTON, DC 20004-2505		X
CoreSite CRP IV Holdings (VCOC I), LLC C/O THE CARLYLE GROUP, 1001 PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH WASHINGTON, DC 20004-2505		X
CoreSite CRP IV Holdings (VCOC II), LLC C/O THE CARLYLE GROUP, 1001 PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH WASHINGTON, DC 20004-2505		X

Signatures
CRP IV AIV GP, L.L.C., By: /s/ Kevin Gasque, Authorized Person		8/7/2020
^**Signature of Reporting Person		Date
CRP IV AIV GP, L.P., By: /s/ Kevin Gasque, Authorized Person		8/7/2020
^**Signature of Reporting Person		Date
CRP IV-A AIV, L.P., By: CRP IV AIV GP, L.P., its general partner, By: /s/ Kevin Gasque, Authorized Person		8/7/2020
^**Signature of Reporting Person		Date
CRQP IV AIV, L.P., By: CRP IV AIV GP, L.P., its general partner, By: /s/ Kevin Gasque, Authorized Person		8/7/2020
^**Signature of Reporting Person		Date
CoreSite CRP IV Holdings (VCOC I), LLC, By: CRQP IV AIV, L.P., its managing member, By: CRP IV AIV GP, L.P., its general partner, By: /s/ Kevin Gasque, Authorized Person		8/7/2020
^**Signature of Reporting Person		Date
CoreSite CRP IV Holdings (VCOC II), LLC, By: CRQP IV AIV, L.P., its managing member, By: CRP IV AIV GP, L.P., its general partner, By: /s/ Kevin Gasque, Authorized Person		8/7/2020
^**Signature of Reporting Person		Date