UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No. 1 )*

NorthWestern Corporation

(Name of Issuer)

Common Stock

(Title of Class of Securities)

668074305

(CUSIP Number)

Mary Ann Shumaker, 480 Pierce St., Birmingham, MI 48009, (248) 647-9200

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

12/31/2013

(Date of Event which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
x  Rule 13d-1(b)
¨  Rule 13d-1(c)
¨  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 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).

 

CUSIP No. 668074305		13G		Page 2 of 3 Pages

1.		NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Munder Capital Management
2.		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (see instructions) (a)    ¨ (b)    ¨
3.		SEC USE ONLY
4.		CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5.		SOLE VOTING POWER 365,178**
		6.		SHARED VOTING POWER   0
		7.		SOLE DISPOSITIVE POWER   385,996**
		8.		SHARED DISPOSITIVE POWER   0

9.		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 385,996**
10.		CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions)    ¨
11.		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 1.0%** See Item 4 of this filing.
12.		TYPE OF REPORTING PERSON (see instructions) IA, HC

 

CUSIP No. 668074305		13G		Page 2 of 3 Pages

Item 1.

	(a)	Name of Issuer NorthWestern Corporation
	(b)	Address of Issuer’s Principal Executive Offices 3010 West 69th Street Sioux Falls, South Dakota 57108

Item 2.

	(a)	Name of Person Filing Munder Capital Management
	(b)	Address of the Principal Office or, if none, residence 480 Pierce Street Birmingham, MI 48009
	(c)	Citizenship Delaware
	(d)	Title of Class of Securities Common Stock
	(e)	CUSIP Number 668074305

Item 3.  If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

	(a)	¨	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).
	(b)	¨	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).
	(c)	¨	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).
	(d)	¨	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).
	(e)	x	An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);
	(f)	¨	An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);
	(g)	x	A parent holding company or control person in accordance with §240.13d-1(b)(1)(ii)(G);
	(h)	¨	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
	(i)	¨	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
	(j)	¨	Group, in accordance with §240.13d-1(b)(1)(ii)(J).

Item 4.  Ownership.

Munder Capital is the sole owner of Integrity Asset Management, LLC (“Integrity”). Due to this ownership structure, holdings for Munder Capital and Integrity are aggregated for purposes of this filing. Munder Capital and Integrity are registered investment advisers, each furnishing investment advice to various investment companies registered under Section 8 of the Investment Company Act of 1940 and to individual and institutional clients (collectively referred to herein as “Managed Portfolios.”)

	(a)		Amount beneficially owned:  385,996
	(b)		Percent of class:  1.0%
	(c)		Number of shares as to which the person has:
			(i)	Sole power to vote or to direct the vote:   365,178
			(ii)	Shared power to vote or to direct the vote: 0
			(iii)	Sole power to dispose or to direct the disposition of: 385,996
			(iv)	Shared power to dispose or to direct the disposition of : 0

Instruction. For computations regarding securities which represent a right to acquire an underlying security see §240.13d-3(d)(1).

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     x.

Instruction. Dissolution of a group requires a response to this item.

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.

	(a)		The following certification shall be included if the statement is filed pursuant to §240.13d-1(b):
			By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and 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.

 

CUSIP No. 668074305		13G		Page 3 of 3 Pages

 

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..