Ownership Submission
FORM 3
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  MSD CAPITAL L P
2. Date of Event Requiring Statement (Month/Day/Year)
08/25/2008
3. Issuer Name and Ticker or Trading Symbol
SemGroup Energy Partners, L.P. [SGLP]
(Last)
(First)
(Middle)
645 FIFTH AVENUE, 21ST FLOOR
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

NEW YORK, NY 10022
6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)
2. Amount of Securities Beneficially Owned
(Instr. 4)
3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)
4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock (1) (2) 2,148,500
I
See Footnote (1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)
2. Date Exercisable and Expiration Date
(Month/Day/Year)
3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)
4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)
6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Total Return Equity Swap (1) (2) (3) (4)   (3)(4)   (3)(4) Common Stock 519,125 $ (3) (4) I See Footnote (1)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
MSD CAPITAL L P
645 FIFTH AVENUE
21ST FLOOR
NEW YORK, NY 10022
    X    
MSD Torchlight, L.P.
645 FIFTH AVENUE
21ST FLOOR
NEW YORK, NY 10022
    X    

Signatures

MSD Capital, L.P. By: MSD Capital Management LLC Its: General Partner By: /s/ Marc R. Lisker Name: Marc R. Lisker Title: Manager and General Counsel 08/27/2008
**Signature of Reporting Person Date

MSD Torchlight, L.P. By: MSD Capital, L.P. Its: General Partner By: MSD Capital Management LLC Its: General Partner By: /s/ Marc R. Lisker Title: Manager and General Counsel 08/27/2008
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) This statement is jointly filed by and on behalf of each of MSD Capital, L.P. ("MSD Capital") and MSD Torchlight, L.P. ("MSD Torchlight"). MSD Torchlight is the record and direct beneficial owner of the securities covered by this statement. MSD Capital is the general partner of MSD Torchlight and may be deemed to indirectly beneficially own securities owned by MSD Torchlight. MSD Capital Management LLC is the general partner of MSD Capital.
(2) Each reporting person states that neither the filing of this statement nor anything herein shall be deemed an admission that such person is, for purposes of Section 16 of the Act or otherwise, the beneficial owner of any securities covered by this statement. Each reporting person disclaims beneficial ownership of the securities covered by this statement, except to the extent of the pecuniary interest of such person in such securities.
(3) On August 21, 2008, MSD Torchlight entered into a cash-settled total return equity swap ("Total Return Swap") with Citibank, NA New York ("Citibank") with a reference price of $8.8167. Under the terms of the Total Return Swap (i) MSD Torchlight will be obligated to pay to Citibank any negative price performance of the 519,125 shares of common stock subject to the Total Return Swap as of the expiration date of the Total Return Swap, plus interest, and (ii) Citibank will be obligated to pay to MSD Torchlight any positive price performance of the 519,125 shares of common stock subject to the Total Return Swap as of the expiration date of such Total Return Swap. Any dividends received by Citibank on the 519,125 shares of common stock during the term of the Total Return Swap will be paid to MSD Torchlight.
(4) All balances will be cash settled at the expiration date of the Total Return Swap. The Total Return Swap expires on August 20, 2018, although MSD Torchlight has the right to terminate and close out the Total Return Swap early if it so chooses. The Total Return Swap does not give MSD Torchlight direct or indirect voting, investment or dispositive control over any securities of the Issuer or require Citibank to acquire, hold, vote or dispose of any securities of the Issuer. Accordingly, MSD Torchlight disclaims any beneficial ownership in securities that may be referenced in the Total Return Swap.
 
Remarks:
Exhibit 99.1 - Joint Filer Information

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