13D Filing: J2 Global Inc (JCOM) Holds Stake in Carbonite Inc (CARB)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE
13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 6)*

CARBONITE,
INC.

(Name of Issuer)

Common Stock,
par value $0.01 per share

(Title of Class of Securities)

141337105

(CUSIP
Number)

Jeremy D. Rossen

Vice President, General Counsel

j2 Global, Inc.

6922
Hollywood Blvd., Suite 500

Los Angeles, California 90028

(323) 860-9200

(Name,
Address and Telephone Number of Person Authorized to Receive Notices and Communications)

February 10, 2016

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box  ¨.

Note: Schedules filed in paper format shall
include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

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

The information required on 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).

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