Bridger Management SC 13G Arrowhead Research Corp

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C.  20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

ARROWHEAD RESEARCH CORPORATION

(Name of Issuer)

Common Stock, $0.001 par value

(Title of Class of Securities)

042797209

(CUSIP Number)

January 13, 2015

(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)

x Rule 13d-1(c)

¨ Rule 13d-1(d)

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).

CUSIP No. 042797209 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Bridger Management LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)	(a) o (b) x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES	5	SOLE VOTING POWER 0
BENEFICIALLY OWNED BY	6	SHARED VOTING POWER 2,984,183
EACH REPORTING	7	SOLE DISPOSITIVE POWER 0
PERSON WITH	8	SHARED DISPOSITIVE POWER 2,984,183

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,984,183
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 5.5%
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) IA

CUSIP No. 042797209 13G

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Roberto Mignone
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)	(a) o (b) x
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION United States

NUMBER OF SHARES	5	SOLE VOTING POWER 0
BENEFICIALLY OWNED BY	6	SHARED VOTING POWER 2,984,183
EACH REPORTING	7	SOLE DISPOSITIVE POWER 0
PERSON WITH	8	SHARED DISPOSITIVE POWER 2,984,183

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,984,183
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 5.5%
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) IN

Item 1(a).                Name of Issuer:  Arrowhead Research Corporation

Item 1(b). Address of Issuer’s Principal Executive Offices:

225 S. Lake Avenue, Suite 1050, Pasadena, California 91101

Item 2(a, b, c). Name of Persons Filing, Address of Principal Business Office, Citizenship:

Bridger Management, LLC, a Delaware limited liability company, 90 Park Avenue, 40th Floor, New York, NY 10016

Mr. Roberto Mignone (“Mr. Mignone”), 90 Park Avenue, 40th Floor, New York, NY 10016. Mr. Mignone is a United States citizen.

Item 2(d). Title of Class of Securities:  Common Stock, $0.001 par value (the “Common Stock”)

Item 2(e). CUSIP Number: 042797209

Item 3. Not Applicable.

Item 4. Ownership.

Information with respect to the Reporting Persons’ ownership of the Common Stock as of January 23, 2015 is incorporated by reference to items (5) - (9) and (11) of the cover page of the respective Reporting Person.

Swiftcurrent Offshore Master Ltd., Swiftcurrent Partners L.P., and Bridger Healthcare Ltd. are the owners of record of the Common Stock reported herein.  Each of Swiftcurrent Offshore Master Ltd., Swiftcurrent Partners L.P. and Bridger Healthcare Ltd. has beneficial ownership of less than five percent of the Common Stock.  Bridger Management LLC is the investment adviser to Swiftcurrent Offshore Master Ltd., Swiftcurrent Partners L.P. and Bridger Healthcare Ltd.  Mr. Mignone is the managing member of Bridger Management, LLC.  Each of Bridger Management LLC and Mr. Mignone may be deemed to share beneficial ownership of the Common Stock reported herein.

Item 5. Ownership of Five Percent or less of a Class:   If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following [    ].

Item 6. Ownership of More than Five Percent on Behalf of Another Person.   See Item 4

Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person.   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.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under §240.14a-11.

[Signature Page Follows:]

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.

DATED:  January 23, 2015

BRIDGER MANAGEMENT, LLC

By: /s/ Roberto Mignone

Roberto Mignone, Managing Member

 /s/ Roberto Mignone

Roberto Mignone, Individually

EXHIBIT INDEX

Exhibit I:           Joint Filing Statement Pursuant to Rule 13d-1(k)

Exhibit I

JOINT FILING STATEMENT

PURSUANT TO RULE 13d-1(k)

 The undersigned acknowledge and agree that the foregoing statement on Schedule 13G, is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13G, shall be filed on behalf of each of the undersigned without the necessity of filing additional joint acquisition statements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate

DATED:  January 23, 2015

BRIDGER MANAGEMENT, LLC

By: /s/ Roberto Mignone

Roberto Mignone, Managing Member

/s/ Roberto Mignone

Roberto Mignone, Individually