SEC Form 4

FORM 4		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 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* CRP IV AIV GP, L.L.C. (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip)	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)
	3. Date of Earliest Transaction (Month/Day/Year) 05/01/2015
	4. If Amendment, Date of Original Filed (Month/Day/Year)	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. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	05/01/2015		M		4,500,000	A	(1)	4,500,000	I	See footnotes(2)(3)(4)
Common Stock	05/01/2015		S		4,500,000	D	$48.67	0	I	See footnotes(2)(3)(4)

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		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: 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
Operating Partnership Units	(1)	05/01/2015		M			4,500,000	(1)	(1)	Common Stock	4,500,000	(1)	20,775,390	I	See footnotes(2)(3)(4)

1. Name and Address of Reporting Person* CRP IV AIV GP, L.L.C. (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* CRP IV AIV GP, L.P. (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* CRP IV-A AIV, L.P. (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* CRQP IV AIV, L.P. (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* CoreSite CRP IV Holdings (VCOC I), LLC (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* CoreSite CRP IV Holdings (VCOC II), LLC (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Carlyle Realty V GP, L.L.C. (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Carlyle Realty V, L.P. (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* CoreSite CRP V Holdings, LLC (Last) (First) (Middle) C/O THE CARLYLE GROUP 1001 PENNSYLVANIA AVE. NW, SUITE 220S (Street) WASHINGTON DC 20004 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

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. Following the transactions reported herein, consists of (i) 5,114,769 common units held by CoreSite CRP III Holdings, LLC; (ii) 1,036,123 common units held by CoreSite CRP III Holdings (VCOC), LLC; (iii) 3,584,431 common units held by CoreSite CRP IV Holdings, LLC; (iv) 610,419 common units held by CoreSite CRP IV Holdings (VCOC I), LLC; (v) 1,568,923 common units held by CoreSite CRP IV Holdings (VCOC II), LLC; and (vi) 8,860,725 common units held by CoreSite CRP V Holdings, LLC.

3. Carlyle Group Management L.L.C. is the general partner of The Carlyle Group L.P., which is a publicly traded entity listed on NASDAQ. The Carlyle Group L.P. is the sole shareholder of Carlyle Holdings I GP Inc., which is the managing member of Carlyle Holdings I GP Sub L.L.C., which is the general partner of Carlyle Holdings I L.P., which is the managing member of TC Group, L.L.C., which is the general partner of TC Group Sub L.P., which is the managing member of each of Carlyle Realty III GP, L.L.C., CRP III AIV GP, L.L.C., Carlyle Realty IV GP, L.L.C., CRP IV AIV GP, L.L.C. and Carlyle Realty V GP, L.L.C.

4. 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 managing 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. Carlyle Realty V GP, L.L.C. is the general partner of Carlyle Realty V, L.P., which is the manager of CoreSite CRP V Holdings, LLC.

Remarks:

Due to the limitations of the electronic filing system Carlyle Group Management L.L.C., The Carlyle Group L.P., Carlyle Holdings I GP Inc., Carlyle Holdings I GP Sub L.L.C., Carlyle Holdings I L.P., TC Group, L.L.C., TC Group Sub L.P., Carlyle Realty III GP, L.L.C., Carlyle Realty III, L.P., CoreSite CRP III Holdings, LLC, CRP III AIV GP, L.L.C., CRP III AIV GP, L.P., CRQP III AIV, L.P., CoreSite CRP III Holdings (VCOC), LLC, Carlyle Realty IV GP, L.L.C., Carlyle Realty IV, L.P., and CoreSite CRP IV Holdings, LLC are filing a separate Form 4.

	/s/ R. Rainey Hoffman, attorney-in-fact for Daniel A. D'Aniello, Chairman	05/05/2015
	** Signature of Reporting Person	Date
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