Edgar Filing: CoreSite Realty Corp

SC 13G/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

CORESITE REALTY CORPORATION

(Name of Issuer)

Common stock, par value $0.01

(Title of Class of Securities)

21870Q105

(CUSIP Number)

December 31, 2012

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

¨ Rule 13d-1(b)

¨ Rule 13d-1(c)

x Rule 13d-1(d)

*	The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13G


CUSIP No. 21870Q105		Page 1 of 41


1	Names of reporting persons The Carlyle Group L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 25,275,390
		7	Sole dispositive power 0
		8	Shared dispositive power 25,275,390
9	Aggregate amount beneficially owned by each reporting person 25,275,390
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 54.5%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 2 of 41


1	Names of reporting persons Carlyle Group Management L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 25,275,390
		7	Sole dispositive power 0
		8	Shared dispositive power 25,275,390
9	Aggregate amount beneficially owned by each reporting person 25,275,390
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 54.5%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 3 of 41


1	Names of reporting persons Carlyle Holdings I GP Inc.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 25,275,390
		7	Sole dispositive power 0
		8	Shared dispositive power 25,275,390
9	Aggregate amount beneficially owned by each reporting person 25,275,390
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 54.5%
12	Type of reporting person CO

SCHEDULE 13G


CUSIP No. 21870Q105		Page 4 of 41


1	Names of reporting persons Carlyle Holdings I GP Sub L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 25,275,390
		7	Sole dispositive power 0
		8	Shared dispositive power 25,275,390
9	Aggregate amount beneficially owned by each reporting person 25,275,390
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 54.5%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 5 of 41


1	Names of reporting persons Carlyle Holdings I L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 25,275,390
		7	Sole dispositive power 0
		8	Shared dispositive power 25,275,390
9	Aggregate amount beneficially owned by each reporting person 25,275,390
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 54.5%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 6 of 41


1	Names of reporting persons TC Group, L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 25,275,390
		7	Sole dispositive power 0
		8	Shared dispositive power 25,275,390
9	Aggregate amount beneficially owned by each reporting person 25,275,390
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 54.5%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 7 of 41


1	Names of reporting persons TC Group Sub L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 25,275,390
		7	Sole dispositive power 0
		8	Shared dispositive power 25,275,390
9	Aggregate amount beneficially owned by each reporting person 25,275,390
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 54.5%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 8 of 41


1	Names of reporting persons Carlyle Realty V GP, L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 10,779,980
		7	Sole dispositive power 0
		8	Shared dispositive power 10,779,980
9	Aggregate amount beneficially owned by each reporting person 10,779,980
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 33.8%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 9 of 41


1	Names of reporting persons Carlyle Realty V, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 10,779,980
		7	Sole dispositive power 0
		8	Shared dispositive power 10,779,980
9	Aggregate amount beneficially owned by each reporting person 10,779,980
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 33.8%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 10 of 41


1	Names of reporting persons CoreSite CRP V Holdings, LLC
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 10,779,980
		7	Sole dispositive power 0
		8	Shared dispositive power 10,779,980
9	Aggregate amount beneficially owned by each reporting person 10,779,980
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 33.8%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 11 of 41


1	Names of reporting persons Carlyle Realty III, GP, L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 6,222,640
		7	Sole dispositive power 0
		8	Shared dispositive power 6,222,640
9	Aggregate amount beneficially owned by each reporting person 6,222,640
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 22.8%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 12 of 41


1	Names of reporting persons Carlyle Realty III, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 6,222,640
		7	Sole dispositive power 0
		8	Shared dispositive power 6,222,640
9	Aggregate amount beneficially owned by each reporting person 6,222,640
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 22.8%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 13 of 41


1	Names of reporting persons CoreSite CRP III Holdings, LLC
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 6,222,640
		7	Sole dispositive power 0
		8	Shared dispositive power 6,222,640
9	Aggregate amount beneficially owned by each reporting person 6,222,640
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 22.8%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 14 of 41


1	Names of reporting persons Carlyle Realty IV GP, L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 4,360,827
		7	Sole dispositive power 0
		8	Shared dispositive power 4,360,827
9	Aggregate amount beneficially owned by each reporting person 4,360,827
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 17.1%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 15 of 41


1	Names of reporting persons Carlyle Realty IV, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 4,360,827
		7	Sole dispositive power 0
		8	Shared dispositive power 4,360,827
9	Aggregate amount beneficially owned by each reporting person 4,360,827
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 17.1%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 16 of 41


1	Names of reporting persons CoreSite CRP IV Holdings, LLC
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 4,360,827
		7	Sole dispositive power 0
		8	Shared dispositive power 4,360,827
9	Aggregate amount beneficially owned by each reporting person 4,360,827
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 17.1%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 17 of 41


1	Names of reporting persons CRP IV AIV GP, L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 2,651,393
		7	Sole dispositive power 0
		8	Shared dispositive power 2,651,393
9	Aggregate amount beneficially owned by each reporting person 2,651,393
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 11.2%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 18 of 41


1	Names of reporting persons CRP IV AIV GP, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 2,651,393
		7	Sole dispositive power 0
		8	Shared dispositive power 2,651,393
9	Aggregate amount beneficially owned by each reporting person 2,651,393
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 11.2%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 19 of 41


1	Names of reporting persons CRQP IV AIV, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 1,908,756
		7	Sole dispositive power 0
		8	Shared dispositive power 1,908,756
9	Aggregate amount beneficially owned by each reporting person 1,908,756
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 8.3%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 20 of 41


1	Names of reporting persons CRP IV-A AIV, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 742,637
		7	Sole dispositive power 0
		8	Shared dispositive power 742,637
9	Aggregate amount beneficially owned by each reporting person 742,637
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 3.4%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 21 of 41


1	Names of reporting persons CoreSite CRP IV Holdings (VCOC II), LLC
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 1,908,756
		7	Sole dispositive power 0
		8	Shared dispositive power 1,908,756
9	Aggregate amount beneficially owned by each reporting person 1,908,756
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 8.3%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 22 of 41


1	Names of reporting persons CoreSite CRP IV Holdings (VCOC I), LLC
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 742,637
		7	Sole dispositive power 0
		8	Shared dispositive power 742,637
9	Aggregate amount beneficially owned by each reporting person 742,637
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 3.4%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 23 of 41


1	Names of reporting persons CRP III AIV GP, L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 1,260,550
		7	Sole dispositive power 0
		8	Shared dispositive power 1,260,550
9	Aggregate amount beneficially owned by each reporting person 1,260,550
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 5.6%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 24 of 41


1	Names of reporting persons CRP III AIV GP, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 1,260,550
		7	Sole dispositive power 0
		8	Shared dispositive power 1,260,550
9	Aggregate amount beneficially owned by each reporting person 1,260,550
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 5.6%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 25 of 41


1	Names of reporting persons CRQP III AIV, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 1,260,550
		7	Sole dispositive power 0
		8	Shared dispositive power 1,260,550
9	Aggregate amount beneficially owned by each reporting person 1,260,550
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 5.6%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 26 of 41


1	Names of reporting persons CoreSite CRP III Holdings (VCOC), LLC
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 1,260,550
		7	Sole dispositive power 0
		8	Shared dispositive power 1,260,550
9	Aggregate amount beneficially owned by each reporting person 1,260,550
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 5.6%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 27 of 41


1	Names of reporting persons DBD Investors V Holdings, L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 0
		7	Sole dispositive power 0
		8	Shared dispositive power 0
9	Aggregate amount beneficially owned by each reporting person 0
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 0.0%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 28 of 41


1	Names of reporting persons DBD Investors V, L.L.C.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 0
		7	Sole dispositive power 0
		8	Shared dispositive power 0
9	Aggregate amount beneficially owned by each reporting person 0
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 0.0%
12	Type of reporting person OO (Limited Liability Company)

SCHEDULE 13G


CUSIP No. 21870Q105		Page 29 of 41


1	Names of reporting persons TCG Holdings II, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 0
		7	Sole dispositive power 0
		8	Shared dispositive power 0
9	Aggregate amount beneficially owned by each reporting person 0
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 0.0%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 30 of 41


1	Names of reporting persons TC Group Investment Holdings, L.P.
2	Check the appropriate box if a member of a group (a) ¨ (b) ¨
3	SEC use only
4	Citizen or place of organization Delaware
Number of shares beneficially owned by each reporting person with		5	Sole voting power 0
		6	Shared voting power 0
		7	Sole dispositive power 0
		8	Shared dispositive power 0
9	Aggregate amount beneficially owned by each reporting person 0
10	Check if the aggregate amount in Row (9) excludes certain shares Not Applicable
11	Percent of class represented by amount in Row 9 0.0%
12	Type of reporting person PN

SCHEDULE 13G


CUSIP No. 21870Q105		Page 31 of 41


ITEM 1.	(a)	Name of Issuer:

		CoreSite Realty Corporation (the “Issuer”)

	(b)	Address of Issuer’s Principal Executive Offices:

		1050 17th Street, Suite 800 Denver, CO, 80265

ITEM 2.

	(a)	Name of Person Filing:

		Each of the following is hereinafter individually referred to as a “Reporting Person” and collectively as the “Reporting Persons.” This statement is filed on behalf of:

		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 V GP, L.L.C. Carlyle Realty V, L.P. CoreSite CRP V Holdings, LLC Carlyle Realty III, GP, L.L.C. Carlyle Realty III, L.P. CoreSite CRP III Holdings, LLC Carlyle Realty IV GP, L.L.C. Carlyle Realty IV, L.P. CoreSite CRP IV Holdings, LLC CRP IV AIV GP, L.L.C. CRP IV AIV GP, L.P. CRQP IV AIV, L.P. CRP IV-A AIV, L.P. CoreSite CRP IV Holdings (VCOC II), LLC CoreSite CRP IV Holdings (VCOC I), 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 DBD Investors V Holdings, L.L.C. DBD Investors V, L.L.C. TCG Holdings II, L.P. TC Group Investment Holdings, L.P.

SCHEDULE 13G


CUSIP No. 21870Q105		Page 32 of 41


		Following an internal reorganization on May 2, 2012, TC Group Investment Holdings, L.P., is no longer the managing member 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. Accordingly, DBD Investors V Holdings, L.L.C., DBD Investors V, L.L.C., TCG Holdings II, L.P. and TC Group Investment Holdings, L.P. may no longer be deemed to beneficially own the shares reported herein.

	(b)	Address of Principal Business Office:

		The address for each of the Reporting Persons is c/o The Carlyle Group, 1001 Pennsylvania Ave. NW, Suite 220 South, Washington, D.C. 20004-2505.

	(c)	Citizenship of each Reporting Person is:

		Each of the Reporting Persons is organized in the state of Delaware.

	(d)	Title of Class of Securities:

		Common stock, par value $0.01 per share (“Common Stock”)

	(e)	CUSIP Number:

		21870Q105

ITEM 3.

	Not applicable.

ITEM 4.

Ownership

Ownership (a-c)

The ownership information presented below represents beneficial ownership of Common Stock as of December 31, 2012, assuming that all limited partnership units of CoreSite, L.P. (“OP Units”) owned by the Reporting Persons are fully converted on a one-for-one basis into shares of Common Stock. Under the limited partnership agreement governing CoreSite, L.P., OP Units may be redeemed for cash or, at the election of the Issuer, for shares of Common Stock on a one-for-one basis. The percent of class presented below is based upon 21,118,457 shares of Common Stock outstanding as of October 31, 2012.

SCHEDULE 13G


CUSIP No. 21870Q105		Page 33 of 41


Reporting Person	Amount beneficially owned		Percent of class:			Sole power to vote or to direct the vote:		Shared power to vote or to direct the vote:		Sole power to dispose or to direct the disposition of:		Shared power to dispose or to direct the disposition of:
Carlyle Group Management L.L.C.		25,275,390		54.5	%		0		25,275,390		0		25,275,390
The Carlyle Group L.P.		25,275,390		54.5	%		0		25,275,390		0		25,275,390
Carlyle Holdings I GP Inc.		25,275,390		54.5	%		0		25,275,390		0		25,275,390
Carlyle Holdings I GP Sub L.L.C.		25,275,390		54.5	%		0		25,275,390		0		25,275,390
Carlyle Holdings I L.P.		25,275,390		54.5	%		0		25,275,390		0		25,275,390
TC Group, L.L.C.		25,275,390		54.5	%		0		25,275,390		0		25,275,390
TC Group Sub L.P.		25,275,390		54.5	%		0		25,275,390		0		25,275,390
Carlyle Realty V GP, L.L.C.		10,779,980		33.8	%		0		10,779,980		0		10,779,980
Carlyle Realty V, L.P.		10,779,980		33.8	%		0		10,779,980		0		10,779,980
CoreSite CRP V Holdings, LLC		10,779,980		33.8	%		0		10,779,980		0		10,779,980
Carlyle Realty III, GP, L.L.C.		6,222,640		22.8	%		0		6,222,640		0		6,222,640
Carlyle Realty III, L.P.		6,222,640		22.8	%		0		6,222,640		0		6,222,640
CoreSite CRP III Holdings, LLC		6,222,640		22.8	%		0		6,222,640		0		6,222,640
Carlyle Realty IV GP, L.L.C.		4,360,827		17.1	%		0		4,360,827		0		4,360,827
Carlyle Realty IV, L.P.		4,360,827		17.1	%		0		4,360,827		0		4,360,827
CoreSite CRP IV Holdings, LLC		4,360,827		17.1	%		0		4,360,827		0		4,360,827
CRP IV AIV GP, L.L.C.		2,651,393		11.2	%		0		2,651,393		0		2,651,393
CRP IV AIV GP, L.P.		2,651,393		11.2	%		0		2,651,393		0		2,651,393
CRQP IV AIV, L.P.		1,908,756		8.3	%		0		1,908,756		0		1,908,756
CRP IV-A AIV, L.P.		742,637		3.4	%		0		742,637		0		742,637
CoreSite CRP IV Holdings (VCOC II), LLC		1,908,756		8.3	%		0		1,908,756		0		1,908,756
CoreSite CRP IV Holdings (VCOC I), LLC		742,637		3.4	%		0		742,637		0		742,637
CRP III AIV GP, L.L.C.		1,260,550		5.6	%		0		1,260,550		0		1,260,550
CRP III AIV GP, L.P.		1,260,550		5.6	%		0		1,260,550		0		1,260,550
CRQP III AIV, L.P.		1,260,550		5.6	%		0		1,260,550		0		1,260,550
CoreSite CRP III Holdings (VCOC), LLC		1,260,550		5.6	%		0		1,260,550		0		1,260,550
DBD Investors V Holdings, L.L.C.		0		0.0	%		0		0		0		0
DBD Investors V, L.L.C.		0		0.0	%		0		0		0		0
TCG Holdings II, L.P.		0		0.0	%		0		0		0		0
TC Group Investment Holdings, L.P.		0		0.0	%		0		0		0		0

CoreSite CRP III Holdings, LLC, CoreSite CRP III Holdings (VCOC), LLC, CoreSite CRP IV Holdings, LLC, CoreSite CRP IV Holdings (VCOC I), LLC, CoreSite CRP IV Holdings (VCOC II), LLC and CoreSite CRP V Holdings, LLC are the record holders of 6,222,640, 1,260,550, 4,360,827, 742,637, 1,908,756 and 10,779,980 OP Units, respectively.

SCHEDULE 13G


CUSIP No. 21870Q105		Page 34 of 41

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.

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

ITEM 5.

Ownership of Five Percent or Less of a Class

Not applicable.

ITEM 6.

Ownership of More than Five Percent on Behalf of Another Person

Not applicable.

ITEM 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company

Not applicable.

ITEM 8.

Identification and Classification of Members of the Group

Not applicable.

ITEM 9.

Notice of Dissolution of Group

Not applicable.

ITEM 10.

Certification

Not applicable

SCHEDULE 13G


CUSIP No. 21870Q105		Page 35 of 41

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: February 14, 2013


CARLYLE GROUP MANAGEMENT L.L.C.

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

THE CARLYLE GROUP L.P.
By: Carlyle Group Management L.L.C., its general partner

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CARLYLE HOLDINGS I GP INC.

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CARLYLE HOLDINGS I GP SUB L.L.C.
By: Carlyle Holdings I GP Inc., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CARLYLE HOLDINGS I L.P.
By: Carlyle Holdings I GP Sub L.L.C., its general partner
By: Carlyle Holdings I GP Inc., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

TC GROUP, L.L.C.
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

SCHEDULE 13G


CUSIP No. 21870Q105		Page 36 of 41


TC GROUP SUB L.P.
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CARLYLE REALTY V GP, L.L.C.
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CARLYLE REALTY V, L.P.
By Carlyle Realty V GP, L.L.C., its general partner By: TC Group Sub, L.P., its managing member

By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CORESITE CRP V HOLDINGS, LLC
By: Carlyle Realty V, L.P., its managing member
By Carlyle Realty V GP, L.L.C., its General Partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CARLYLE REALTY III, GP, L.L.C.
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

SCHEDULE 13G


CUSIP No. 21870Q105		Page 37 of 41


CARLYLE REALTY III, L.P.
By: Carlyle Realty III, GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CORESITE CRP III HOLDINGS, LLC
By: Carlyle Realty III, L.P., its managing member
By: Carlyle Realty III, GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CRP III AIV GP, L.L.C.
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CRP III AIV GP, L.P.
By: CRP III AIV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

SCHEDULE 13G


CUSIP No. 21870Q105		Page 38 of 41


CRQP III AIV, L.P.
By: CRP III AIV GP, L.P., its general partner
By: CRP III AIV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CORESITE CRP III HOLDINGS (VCOC), LLC
By: CRQP III AIV, L.P., its managing member
By: CRP III AIV GP, L.P., its general partner
By: CRP III AIV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CARLYLE REALTY IV GP, L.L.C.
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CARLYLE REALTY IV, L.P.
By: Carlyle Realty IV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

SCHEDULE 13G


CUSIP No. 21870Q105		Page 39 of 41


CORESITE CRP IV HOLDINGS, LLC
By: Carlyle Realty IV, L.P., its managing member
By: Carlyle Realty IV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CRP IV AIV GP, L.L.C.
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CRP IV AIV GP, L.P.
By: CRP IV AIV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

CRP IV-A AIV, L.P.
By: CRP IV AIV GP, L.P. , its general partner
By: CRP IV AIV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

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: CRP IV AIV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

SCHEDULE 13G


CUSIP No. 21870Q105		Page 40 of 41


CRQP IV AIV, L.P.
By: CRP IV AIV GP, L.P., its general partner
By: CRP IV AIV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

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: CRP IV AIV GP, L.L.C., its general partner
By: TC Group Sub, L.P., its managing member
By: TC Group, L.L.C., its general partner
By: Carlyle Holdings I L.P., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Chairman

DBD INVESTORS V HOLDINGS, L.L.C.

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Managing Director

DBD INVESTORS V, L.L.C.
by: DBD Investors V Holdings, L.L.C., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Managing Director

TCG HOLDINGS II, L.P.
by: DBD Investors V, L.L.C., its general partner
by: DBD Investors V Holdings, L.L.C., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Managing Director

SCHEDULE 13G


CUSIP No. 21870Q105		Page 41 of 41


TC GROUP INVESTMENT HOLDINGS, L.P.
by: TCG Holdings II, L.P., its general partner
by: DBD Investors V, L.L.C., its general partner
by: DBD Investors V Holdings, L.L.C., its managing member

By:		/s/ R. Rainey Hoffman, attorney-in-fact
Name:		Daniel D’Aniello
Title:		Managing Director

LIST OF EXHIBITS


Exhibit No.		Description

24		Power of Attorney

99		Joint Filing Agreement