SC 13G/A

0001362310-09-002100.txt : 20090217 0001362310-09-002100.hdr.sgml : 20090216 20090217060157 ACCESSION NUMBER: 0001362310-09-002100 CONFORMED SUBMISSION TYPE: SC 13G/A PUBLIC DOCUMENT COUNT: 2 FILED AS OF DATE: 20090217 DATE AS OF CHANGE: 20090217 GROUP MEMBERS: ALEC N. LITOWITZ GROUP MEMBERS: MAGNETAR CAPITAL PARTNERS LP GROUP MEMBERS: SUPERNOVA MANAGEMENT LLC SUBJECT COMPANY: COMPANY DATA: COMPANY CONFORMED NAME: MARKWEST ENERGY PARTNERS L P CENTRAL INDEX KEY: 0001166036 STANDARD INDUSTRIAL CLASSIFICATION: CRUDE PETROLEUM & NATURAL GAS [1311] IRS NUMBER: 270005456 FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SC 13G/A SEC ACT: 1934 Act SEC FILE NUMBER: 005-79896 FILM NUMBER: 09606675 BUSINESS ADDRESS: STREET 1: 1515 ARAPAHOE STREET STREET 2: TOWER 2, SUITE 700 CITY: DENVER STATE: CO ZIP: 80202-2126 BUSINESS PHONE: 303-925-9200 MAIL ADDRESS: STREET 1: 1515 ARAPAHOE STREET STREET 2: TOWER 2, SUITE 700 CITY: DENVER STATE: CO ZIP: 80202-2126 FILED BY: COMPANY DATA: COMPANY CONFORMED NAME: Magnetar Financial LLC CENTRAL INDEX KEY: 0001352851 IRS NUMBER: 043818748 STATE OF INCORPORATION: DE FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SC 13G/A BUSINESS ADDRESS: STREET 1: 1603 ORRINGTON AVE. STREET 2: 13TH FLOOR CITY: EVANSTON STATE: IL ZIP: 60201 BUSINESS PHONE: (847)905-4400 MAIL ADDRESS: STREET 1: 1603 ORRINGTON AVE. STREET 2: 13TH FLOOR CITY: EVANSTON STATE: IL ZIP: 60201 SC 13G/A 1 c80731sc13gza.htm SC 13G/A SC 13G/A


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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

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

MARKWEST ENERGY PARTNERS, L.P.

(Name of Issuer)

Common Units

(Title of Class of Securities)

570759100

(CUSIP Number)

December 31, 2008

(Date of Event Which Requires Filing of this Statement)

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

þ Rule 13d-1(b)

o Rule 13d-1(c)

o 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).


CUSIP No.		570759100


1	NAMES OF REPORTING PERSONS MAGNETAR FINANCIAL LLC


2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a) o
	(b) o

3	SEC USE ONLY



4	CITIZENSHIP OR PLACE OF ORGANIZATION

	Delaware

		5	SOLE VOTING POWER

NUMBER OF			0

SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			43,002

EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER

			43,002

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

	43,002

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)

	0.08% based on 56,639,952 shares outstanding as of October 31, 2008.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

	IA; OO


CUSIP No.		570759100


1	NAMES OF REPORTING PERSONS MAGNETAR CAPITAL PARTNERS LP


2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a) o
	(b) o

3	SEC USE ONLY



4	CITIZENSHIP OR PLACE OF ORGANIZATION

	Delaware

		5	SOLE VOTING POWER

NUMBER OF			0

SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			43,002

EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER

			43,002

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

	43,002

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)

	0.08% based on 56,639,952 shares outstanding as of October 31, 2008.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

	HC; OO


CUSIP No.		570759100


1	NAMES OF REPORTING PERSONS SUPERNOVA MANAGEMENT LLC


2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a) o
	(b) o

3	SEC USE ONLY



4	CITIZENSHIP OR PLACE OF ORGANIZATION

	Delaware

		5	SOLE VOTING POWER

NUMBER OF			0

SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			43,002

EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER

			43,002

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

	43,002

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)

	0.08% based on 56,639,952 shares outstanding as of October 31, 2008.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

	HC; OO


CUSIP No.		570759100


1	NAMES OF REPORTING PERSONS ALEC N. LITOWITZ


2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a) o
	(b) o

3	SEC USE ONLY



4	CITIZENSHIP OR PLACE OF ORGANIZATION

	United States of America

		5	SOLE VOTING POWER

NUMBER OF			0

SHARES		6	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			43,002

EACH		7	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER

			43,002

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

	43,002

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)

	0.08% based on 56,639,952 shares outstanding as of October 31, 2008.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

	HC

SCHEDULE 13G/A


Item 1(a)		Name of Issuer.

Markwest Energy Partners, L.P. (the “Issuer”)


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

1515 Arapahoe Street, Tower 2, Suite 700, Denver, Colorado 80202


Item 2(a)		Name of Person Filing.

This statement is filed on behalf of each of the following person (collectively, the “Reporting Persons”):

	i)		Magnetar Financial LLC (“Magnetar Financial”);

	ii)		Magnetar Capital Partners LP (Magnetar Capital Partners”);

	iii)		Supernova Management LLC (“Supernova Management”); and

	iv)		Alec N. Litowitz (“Mr. Litowitz”).

This Statement relates to Shares (as defined herein) held for the account of Manager Capital Master Fund, Ltd, a Cayman Islands exempted company (“Magnetar Capital Master Fund”). Magnetar Capital Partners serves as the sole member and parent holding company of Magnetar Financial. Magnetar Financial is a registered investment adviser under Section 203 of the Investment Advisers Act of 1940, as amended. Magnetar Financial serves as investment adviser to Magnetar Capital Master Fund. In such capacity, Magnetar Financial exercises voting and investment power over the Shares held for the account of Magnetar Capital Master Fund. Supernova Management is the general partner of Magnetar Capital Partners. The manager of Supernova Management is Mr. Litowitz.


Item 2(b)		Address of Principal Business Office.

The address of the principal business office of each of Magnetar Financial, Magnetar Capital Partners, Supernova Management, and Mr. Litowitz is 1603 Orrington Avenue, 13^th Floor, Evanston, Illinois 60201.


Item 2(c)		Place of Organization.

	i)		Magnetar Financial is Delaware limited liability company;

	ii)		Magnetar Capital Partners is a Delaware limited partnership;

	iii)		Supernova Management is a Delaware limited liability company; and

	iv)		Mr. Litowitz is a citizen of the United States of America.


Item 2(d)		Title of Class of Securities.

Common Units (the “Shares”)


Item 2(e)		CUSIP Number.

570759100


Item 3		Reporting Person.

(a) o Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);

(b) o Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);

(d) o Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C 80a–8);

(e) þ An investment adviser in accordance with §240.13d–1(b)(1)(ii)(E);

(f) o An employee benefit plan or endowment fund in accordance with §240.13d–1(b)(1)(ii)(F);

(g) o A parent holding company or control person in accordance with §240.13d—1(b)(1)(ii)(G);

(h) o A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i) o 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) o A non-U.S. institution in accordance with §240.13d—1(b)(1)(ii)(J);

(k) o Group, in accordance with §240.13d—1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with §240.13d—1(b)(1)(ii)(J), please specify the type of institution:


Item 4		Ownership.


Item 4(a)		Amount Beneficially Owned:

As of December 31, 2008, each of Magnetar Financial, Magnetar Capital Partners, Supernova Management and Mr. Litowitz may be deemed to be the beneficial owner of 43,002 Shares held for the account of the Magnetar Capital Master Fund.


Item 4(b)		Percent of Class:

The number of Shares of which each of Magnetar Financial, Magnetar Capital Partners, Supernova Management and Mr. Litowitz may be deemed to be the beneficial owner constitutes .08% the total number of Shares outstanding (based upon information provided by the Issuer in its most recently filed registration statement on Form 10-Q filed on November 10, 2008, there were approximately 56,639,952 shares as of October 31, 2008).


Item4(c)		Number of Shares of which such person has:

Magnetar Financial, Magnetar Capital Partners, Supernova Management, and Mr. Litowitz:


(i)	Sole power to vote or to direct the vote:	0
(ii)	Shared power to vote or to direct the vote :	43,002


(iii)	Sole power to dispose or to direct the disposition of:	0
(iv)	Shared power to dispose or to direct the disposition of:	43,002


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 5 percent of the class of securities, check the following þ.


Item 6		Ownership of More Than Five Percent on Behalf of Another Person.

This Item 6 is not applicable.


Item 7		Identification and Classification of the Subsidiary which Acquired the Security Being Reported On by the Parent Holding Company.

See disclosure Item 2.


Item 8		Identification and Classification of Members of the Group.

This Item 8 is not applicable.


Item 9		Notice of Dissolution of Group.

This Item 9 is not applicable.


Item 10		Certification.

By signing below the Reporting Persons certifies that, to the best of their 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.

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 17, 2009	MAGNETAR FINANCIAL LLC
	By:	Magnetar Capital Partners LP, its Sole Member

	By:	/s/ Alec N. Litowitz
		Name:	Alec N. Litowitz
		Title:	Manager of Supernova Management LLC, the General Partner of Magnetar Capital Partners LP


Date: February 17, 2009	MAGNETAR CAPITAL PARTNERS LP
	By:	/s/ Alec N. Litowitz
		Name:	Alec N. Litowitz
		Title:	Manager of Supernova Management LLC, the General Partner of Magnetar Capital Partners LP


Date: February 17, 2009	SUPERNOVA MANAGEMENT LLC
	By:	/s/ Alec N. Litowitz
		Name:	Alec N. Litowitz
		Title:	Manager



Date: February 17, 2009	/s/ Alec N. Litowitz
	Alec N. Litowitz

EXHIBIT INDEX


Ex.
A		Joint Filing Agreement, dated February 17, 2009 by and among Magnetar Financial LLC, Magnetar Capital Partners LP, Supernova Management LLC, and Alec N. Litowitz......

EX-1 2 c80731exv1.htm EXHIBIT A Filed by Bowne Pure Compliance

EXHIBIT A

JOINT FILING AGREEMENT

The undersigned hereby agree that the statement on Schedule 13G with respect to the Common Stock of Markwest Energy Partners, L.P. dated as of February 17, 2009 is, and any amendments thereto (including amendments on Schedule 13D) signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the previsions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended.


Date: February 17, 2009	MAGNETAR FINANCIAL LLC
	By:	Magnetar Capital Partners LP, its Sole Member

	By:	/s/ Alec N. Litowitz
		Name:	Alec N. Litowitz
		Title:	Manager of Supernova Management LLC, the General Partner of Magnetar Capital Partners LP

Date: February 17, 2009	MAGNETAR CAPITAL PARTNERS LP
	By:	/s/ Alec N. Litowitz
		Name:	Alec N. Litowitz
		Title:	Manager of Supernova Management LLC, the General Partner of Magnetar Capital Partners LP

Date: February 17, 2009	SUPERNOVA MANAGEMENT LLC
	By:	/s/ Alec N. Litowitz
		Name:	Alec N. Litowitz
		Title:	Manager

Date: February 17, 2009	/s/ Alec N. Litowitz
	Alec N. Litowitz