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|            |
| (Mark One) |

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| x | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 |

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|   |  |
| o | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 |

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|                                                               |  |  |
| Delaware                                                      |   | 20-3533152 |
| (State or other jurisdiction ofincorporation or organization) |   | (I.R.S. EmployerIdentification No.) |

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|----------------------------------------------------------------------------------|
|                                                                                  |  |  |
| Title of Each Class                                               |   | Name of Each Exchange on Which Registered |
| Class A Common Stock, par value $0.01 per shareWarrants to Purchase Common Stock |   | New York Stock ExchangeNew York Stock Exchange |

|                                   |
|-----------------------------------|
|                                   |  |  |  |  |  |
| Large Accelerated Filer | ý |    |   | Accelerated Filer | o |
|                              |   |   |   |   |
| Non-Accelerated Filer        | o |    | (Do not check if a smaller reporting company) | Smaller Reporting Company | o |

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|     |                                                                                                                                                                                       |
|-----|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| (1) | Financial Statements. The consolidated financial statements of the Company included in this Form 10-K are listed on page F-1, which follows the signature page to this Form 10-K. |

|     |                                                                                                                                                                                                     |
|-----|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| (2) | Financial Statement Schedules. All financial statement schedules are omitted as inapplicable or because the required information is contained in the financial statements or the notes thereto. |

|     |                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|-----|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| (3) | Exhibits. The following documents are included as exhibits to this Amendment No. 1. Those exhibits below incorporated by reference herein are indicated as such by the information supplied in the parenthetical thereafter. If no parenthetical appears after an exhibit, such exhibit is filed with this Amendment No. 1 or, except as otherwise noted, was filed with the Form 10-K of the Registrant filed on March 1, 2013. |

|               |
|---------------|
|               |  |  |
| ExhibitNumber |    | Description |
|          |   |
| 2.1           |    | Fourth Amended Joint Plan of Affiliated Debtors filed with the United States Bankruptcy Court for the District of Delaware on October 27, 2009 (filed as Exhibit 2.1 to our registration statement on Form 10, File No. 001-34736 (the “Form 10”)). |
|          |   |
| 2.2           |    | Contribution Agreement dated August 31, 2011, among SemStream, L.P., a wholly-owned subsidiary of SemGroup Corporation, NGL Supply Terminal Company LLC, NGL Energy Partners LP and NGL Energy Holdings LLC (filed as Exhibit 2.1 to our current report on Form 8-K dated November 1, 2011, filed November 4, 2011). |
|          |   |
| 2.3           |    | Second Amended and Restated Limited Liability Company Agreement of NGL Energy Holdings LLC (filed as Exhibit 2.2 to our current report on Form 8-K dated November 1, 2011, filed November 4, 2011). |
|          |   |
| 2.4           |    | First Amended and Restated Registration Rights Agreement dated October 3, 2011, among NGL Energy Partners LP, Hicks Oil & Hicksgas, Incorporated, NGL Holdings, Inc., Krim2010, LLC, Infrastructure Capital Management, LLC, Atkinson Investors, LLC, Stanley A. Bugh, Robert R. Foster, Brian K. Pauling, Stanley D. Perry, Stephen D. Tuttle, Craig S. Jones, Daniel Post, Mark McGinty, Sharra Straight, David Eastin, AO Energy, Inc., E. Osterman, Inc., E. Osterman Gas Service, Inc., E. Osterman Propane, Inc., Milford Propane, Inc., Osterman Propane, Inc., Propane Gas, Inc., and Saveway Propane Gas Service, Inc. (filed as Exhibit 2.3 to our current report on Form 8-K dated November 1, 2011, filed November 4, 2011). |
|          |   |
| 2.5           |    | Amendment No. 1 and Joinder to First Amended and Restated Registration Rights Agreement dated November 1, 2011, between NGL Energy Holdings LLC and SemStream, L.P. (filed as Exhibit 2.4 to our current report on Form 8-K dated November 1, 2011, filed November 4, 2011). |
|          |   |
| 2.6           |   | Contribution Agreement, dated as of January 8, 2013, by and among SemGroup Corporation, Rose Rock Midstream Holdings, LLC, Rose Rock Midstream GP, LLC, Rose Rock Midstream, L.P. and Rose Rock Midstream Operating, L.L.C. (filed as Exhibit 2.1 to our current report on Form 8-K dated January 8, 2013, filed January 14, 2013). |
|          |   |   |
| 3.1           |    | Amended and Restated Certificate of Incorporation, dated as of November 30, 2009, of SemGroup Corporation (filed as Exhibit 3.1 to the Form 10). |
|          |   |
| 3.2           |    | Amended and Restated Bylaws, dated as of October 28, 2011, of SemGroup Corporation (filed as Exhibit 3.1 to our current report on Form 8-K dated October 28, 2011, filed October 28, 2011). |
|          |   |
| 4.1           |    | Form of stock certificate for our Class A Common Stock, par value $0.01 per share (filed as Exhibit 4.1 to the Form 10). |
|          |   |
| 4.2           |    | Form of stock certificate for our Class B Common Stock, par value $0.01 per share (filed as Exhibit 4.2 to the Form 10). |
|          |   |
| 4.3           |    | Warrant Agreement dated as of November 30, 2009, by and between SemGroup Corporation and Mellon Investor Services, LLC (filed as Exhibit 4.3 to the Form 10). |
|          |   |   |
| 4.4           |    | Form of warrant certificate (filed as Exhibit 4.4 to the Form 10). |
|          |   |
| 4.5*          |    | First Amendment to Warrant Agreement, dated as of November 1, 2012, by and between SemGroup Corporation and Computershare Shareowner Services LLC (successor-in-interest to Mellon Investor Services, LLC). |
|          |   |

----

|               |
|---------------|
|               |  |  |
| ExhibitNumber |    | Description |
| 10.1          |    | Credit Agreement (the “Credit Facility”) dated as of June 17, 2011, among SemGroup Corporation, as borrower, the lenders parties thereto from time to time, and The Royal Bank of Scotland PLC, as Administrative Agent and Collateral Agent (filed as Exhibit 10 to our current report on Form 8-K dated June 17, 2011, filed June 21, 2011). |
|          |   |
| 10.2          |    | Second Amendment to the Credit Facility, dated as of September 19, 2011 (filed as Exhibit 10 to our current report on Form 8-K dated September 19, 2011, filed September 23, 2011). |
|          |   |
| 10.3+         |    | SemGroup Corporation Board of Directors Compensation Plan (filed as Exhibit 10.6 to the Form 10). |
|          |   |
| 10.4+         |    | SemGroup Corporation Nonexecutive Directors’ Compensation Deferral Program (filed as Exhibit 10.7 to the Form 10). |
|          |   |
| 10.5+         |    | SemGroup Corporation Equity Incentive Plan (filed as Exhibit 10.8 to the Form 10). |
|          |   |
| 10.6+         |    | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for Directors (filed as Exhibit 10.9 to the Form 10). |
|          |   |
| 10.7+         |    | Amendment No. 1 to SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for Directors (filed as Exhibit 10.15 to the Form 10). |
|          |   |
| 10.8+         |    | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States (filed as Exhibit 10.10 to the Form 10). |
|          |   |
| 10.9+         |    | Amendment No. 1 to SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States (filed as Exhibit 10.16 to the Form 10). |
|          |   |
| 10.10+        |    | Amendment No. 2 to SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States (filed as Exhibit 10.10 to our annual report on Form 10-K for the fiscal year ended December 31, 2011, filed February 29, 2012 (the "2011 Form 10-K")). |
|          |   |
| 10.11+        |    | Employment Agreement dated as of November 30, 2009, by and among SemManagement, L.L.C., SemGroup Corporation and Norman J. Szydlowski (filed as Exhibit 10.11 to the Form 10). |
|          |   |
| 10.12+        |    | Letter Amendment dated March 18, 2010, by and among SemManagement, L.L.C., SemGroup Corporation and Norman J. Szydlowski, amending the Employment Agreement dated as of November 30, 2009 (filed as Exhibit 10.12 to the Form 10). |
|          |   |
| 10.13+        |    | Form of Severance Agreement between SemGroup Corporation and each of its executive officers other than Norman J. Szydlowski (filed as Exhibit 10.13 to the Form 10). |
|          |   |
| 10.14+        |    | Form of Amendment to Severance Agreement between SemGroup Corporation and certain of its executive officers (filed as Exhibit 10.14 to the 2011 Form 10-K). |
|          |   |
| 10.15+        |    | SemGroup Corporation Equity Incentive Plan Form of Retention Award Agreement for certain executive officers (filed as Exhibit 10.14 to the Form 10). |
|          |   |
| 10.16+        |    | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for Directors for awards granted on or after August 31, 2010 (filed as Exhibit 10.17 to the Form 10). |
|          |   |
| 10.17+        |    | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States for awards granted on or after August 31, 2010 (filed as Exhibit 10.18 to the Form 10). |
|          |   |
| 10.18+        |   | Form of 2011 Performance Share Unit Award Agreement under the SemGroup Corporation Equity Incentive Plan for executive officers (filed as Exhibit 10.1 to our current report on Form 8-K dated January 24, 2011, filed January 24, 2011). |
|          |   |
| 10.19+        |   | Form of Restricted Stock Award Agreement under the SemGroup Corporation Equity Incentive Plan for executive officers and employees in the United States during 2011 (filed as Exhibit 10.2 to our current report on Form 8-K dated January 24, 2011, filed January 24, 2011). |
|          |   |
| 10.20+        |   | Form of 2012 Performance Share Unit Award Agreement under the SemGroup Corporation Equity Incentive Plan for executive officers (filed as Exhibit 10.20 to the 2011 Form 10-K). |
|          |   |
| 10.21+        |   | Form of Restricted Stock Award Agreement under the SemGroup Corporation Equity Incentive Plan for executive officers and employees in the United States for awards granted on or after January 1, 2012 (filed as Exhibit 10.21 to the 2011 Form 10-K). |
|          |   |

----

|               |
|---------------|
|               |  |  |
| ExhibitNumber |    | Description |
| 10.22+        |   | SemGroup Corporation Short-Term Incentive Program (filed as Exhibit 10.1 to our current report on Form 8-K dated February 24, 2011, filed March 2, 2011). |
|          |   |
| 10.23+        |   | Consulting Services Agreement, effective as of February 2, 2012, by and between SemGroup Corporation and David B. Gorte (filed as Exhibit 10.23 to the 2011 Form 10-K). |
|          |   |
| 10.24         |   | Credit Agreement dated November 10, 2011, among Rose Rock Midstream, L.P., as borrower, The Royal Bank of Scotland PLC, as administrative agent and collateral agent, the other agents party thereto and the lenders and issuing banks party thereto (filed as Exhibit 10.1 to Rose Rock Midstream, L.P.’s registration statement on Form S-1, File No. 333-176260). |
|          |   |
| 10.25         |   | Second Amended and Restated Agreement of Limited Partnership of Rose Rock Midstream, L.P. (filed as Exhibit 3.1 to Rose Rock Midstream, L.P.’s current report on Form 8-K dated December 14, 2011, filed December 20, 2011). |
|          |   |
| 10.26         |   | First Amended and Restated Limited Liability Company Agreement of Rose Rock Midstream GP, LLC (filed as Exhibit 3.2 to Rose Rock Midstream, L.P.’s current report on Form 8-K dated December 14, 2011, filed December 20, 2011). |
|          |   |
| 10.27+        |   | Rose Rock Midstream Equity Incentive Plan (filed as Exhibit 10.1 to Rose Rock Midstream, L.P.’s current report on Form 8-K dated December 8, 2011, filed December 14, 2011). |
|          |   |
| 10.28+        |   | Form of Restricted Unit Award Agreement (Employees) under the Rose Rock Midstream Equity Incentive Plan (filed as Exhibit 10.3.1 to Rose Rock Midstream, L.P.’s annual report on Form 10-K for the fiscal year ended December 31, 2011, filed February 29, 2012). |
|          |   |
| 10.29         |   | Fifth Amendment to the Credit Facility, dated as of September 26, 2012 (filed as Exhibit 10.1 to our quarterly report on Form 10-Q for the quarter ended September 30, 2012, filed November 9, 2012). |
|          |   |   |
| 10.30         |   | First Amendment, dated as of September 26, 2012, to the Credit Agreement among Rose Rock Midstream, L.P., certain subsidiaries of Rose Rock Midstream, L.P., as guarantors, the lenders party thereto and The  Royal Bank of Scotland plc, as administrative agent and collateral agent for the lenders (filed as Exhibit 10.2 to our quarterly report on Form 10-Q for the quarter ended September 30, 2012, filed November 9, 2012). |
|          |   |   |
| 10.31+**      |   | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for Directors for awards granted on or after May 22, 2012. |
|          |   |   |
| 10.32         |   | Amendment No. 1 to the Second Amended and Restated Agreement of Limited Partnership of Rose Rock Midstream, L.P. (filed as Exhibit 3.1 to Rose Rock Midstream, L.P.'s current report on Form 8-K dated January 8, 2013, filed January 14, 2013). |
|          |   |   |
| 10.33+*       |   | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States for awards granted on or after March 1, 2013. |
|          |   |   |
| 10.34+*       |   | SemGroup Corporation Equity Incentive Plan Form of Performance Share Unit Award Agreement for executive officers for awards granted on or after March 1, 2013. |
|          |   |   |
| 10.35+*       | ` | Form of Restricted Unit Award Agreement (Employees) under the Rose Rock Midstream Equity Incentive Plan for awards granted on or after March 1, 2013. |
|          |   |   |
| 21*           |   | Subsidiaries of SemGroup Corporation. |
|          |   |
| 23.1*         |   | Consent of Independent Registered Public Accounting Firm. |
|          |   |
| 31.1**        |   | Rule 13a – 14(a)/15d – 14(a) Certification of Norman J. Szydlowski, Chief Executive Officer. |
|          |   |
| 31.2**        |   | Rule 13a – 14(a)/15d – 14(a) Certification of Robert N. Fitzgerald, Chief Financial Officer. |
|          |   |
| 32.1**        |   | Section 1350 Certification of Norman J. Szydlowski, Chief Executive Officer. |
|          |   |
| 32.2**        |   | Section 1350 Certification of Robert N. Fitzgerald, Chief Financial Officer. |
|          |   |
| 99.1**        |   | White Cliffs Pipeline, L.L.C. financial statements presented pursuant to Rule 3-09 of Regulation S-X. |
|          |   |

----

|               |
|---------------|
|               |  |  |
| ExhibitNumber |    | Description |
| 101*          |   | Interactive data files pursuant to Rule 405 of Regulation S-T: (i) the Consolidated Balance Sheets at December 31, 2012 and 2011, (ii) the Consolidated Statements of Operations and Comprehensive Income (Loss) for the years ended December 31, 2012, 2011 and 2010, (iii) the Consolidated Statements of Changes in Owners’ Equity for the years ended December 31, 2012, 2011 and 2010, (iv) the Consolidated Statements of Cash Flows for the years ended December 31, 2012, 2011 and 2010, and (v) the Notes to Consolidated Financial Statements. |

|        |
|--------|
|        |  |
| *      | Previously filed with the Form 10-K of the Registrant filed on March 1, 2013. |
|   |   |
| **     | Filed or furnished, as applicable, with this Amendment No. 1. |
|   |   |
| +      | Management contract or compensatory plan or arrangement |

----

|                     |
|---------------------|
|                     |  |  |
|                | SEMGROUP CORPORATION |
| Date: March 1, 2013 |   |   |
|                | By: |  /s/ Robert N. Fitzgerald |
|                | Robert N. Fitzgerald |
|                | Senior Vice President and |
|                | Chief Financial Officer |

----

|               |
|---------------|
|               |  |  |
| ExhibitNumber |    | Description |
|          |   |
| 2.1           |    | Fourth Amended Joint Plan of Affiliated Debtors filed with the United States Bankruptcy Court for the District of Delaware on October 27, 2009 (filed as Exhibit 2.1 to our registration statement on Form 10, File No. 001-34736 (the “Form 10”)). |
|          |   |
| 2.2           |    | Contribution Agreement dated August 31, 2011, among SemStream, L.P., a wholly-owned subsidiary of SemGroup Corporation, NGL Supply Terminal Company LLC, NGL Energy Partners LP and NGL Energy Holdings LLC (filed as Exhibit 2.1 to our current report on Form 8-K dated November 1, 2011, filed November 4, 2011). |
|          |   |
| 2.3           |    | Second Amended and Restated Limited Liability Company Agreement of NGL Energy Holdings LLC (filed as Exhibit 2.2 to our current report on Form 8-K dated November 1, 2011, filed November 4, 2011). |
|          |   |
| 2.4           |    | First Amended and Restated Registration Rights Agreement dated October 3, 2011, among NGL Energy Partners LP, Hicks Oil & Hicksgas, Incorporated, NGL Holdings, Inc., Krim2010, LLC, Infrastructure Capital Management, LLC, Atkinson Investors, LLC, Stanley A. Bugh, Robert R. Foster, Brian K. Pauling, Stanley D. Perry, Stephen D. Tuttle, Craig S. Jones, Daniel Post, Mark McGinty, Sharra Straight, David Eastin, AO Energy, Inc., E. Osterman, Inc., E. Osterman Gas Service, Inc., E. Osterman Propane, Inc., Milford Propane, Inc., Osterman Propane, Inc., Propane Gas, Inc., and Saveway Propane Gas Service, Inc. (filed as Exhibit 2.3 to our current report on Form 8-K dated November 1, 2011, filed November 4, 2011). |
|          |   |
| 2.5           |    | Amendment No. 1 and Joinder to First Amended and Restated Registration Rights Agreement dated November 1, 2011, between NGL Energy Holdings LLC and SemStream, L.P. (filed as Exhibit 2.4 to our current report on Form 8-K dated November 1, 2011, filed November 4, 2011). |
|          |   |
| 2.6           |   | Contribution Agreement, dated as of January 8, 2013, by and among SemGroup Corporation, Rose Rock Midstream Holdings, LLC, Rose Rock Midstream GP, LLC, Rose Rock Midstream, L.P. and Rose Rock Midstream Operating, L.L.C. (filed as Exhibit 2.1 to our current report on Form 8-K dated January 8, 2013, filed January 14, 2013). |
|          |   |   |
| 3.1           |    | Amended and Restated Certificate of Incorporation, dated as of November 30, 2009, of SemGroup Corporation (filed as Exhibit 3.1 to the Form 10). |
|          |   |
| 3.2           |    | Amended and Restated Bylaws, dated as of October 28, 2011, of SemGroup Corporation (filed as Exhibit 3.1 to our current report on Form 8-K dated October 28, 2011, filed October 28, 2011). |
|          |   |
| 4.1           |    | Form of stock certificate for our Class A Common Stock, par value $0.01 per share (filed as Exhibit 4.1 to the Form 10). |
|          |   |
| 4.2           |    | Form of stock certificate for our Class B Common Stock, par value $0.01 per share (filed as Exhibit 4.2 to the Form 10). |
|          |   |
| 4.3           |    | Warrant Agreement dated as of November 30, 2009, by and between SemGroup Corporation and Mellon Investor Services, LLC (filed as Exhibit 4.3 to the Form 10). |
|          |   |
| 4.4           |    | Form of warrant certificate (filed as Exhibit 4.4 to the Form 10). |
|          |   |
| 4.5*          |    | First Amendment to Warrant Agreement, dated as of November 1, 2012, by and between SemGroup Corporation and Computershare Shareowner Services LLC (successor-in-interest to Mellon Investor Services, LLC). |
|          |   |
| 10.1          |    | Credit Agreement (the “Credit Facility”) dated as of June 17, 2011, among SemGroup Corporation, as borrower, the lenders parties thereto from time to time, and The Royal Bank of Scotland PLC, as Administrative Agent and Collateral Agent (filed as Exhibit 10 to our current report on Form 8-K dated June 17, 2011, filed June 21, 2011). |
|          |   |
| 10.2          |    | Second Amendment to the Credit Facility, dated as of September 19, 2011 (filed as Exhibit 10 to our current report on Form 8-K, dated September 19, 2011, filed September 23, 2011). |
|          |   |
| 10.3+         |    | SemGroup Corporation Board of Directors Compensation Plan (filed as Exhibit 10.6 to the Form 10). |

----

|               |
|---------------|
|               |  |  |
| ExhibitNumber |    | Description |
|          |   |
| 10.4+         |    | SemGroup Corporation Nonexecutive Directors’ Compensation Deferral Program (filed as Exhibit 10.7 to the Form 10). |
|          |   |
| 10.5+         |    | SemGroup Corporation Equity Incentive Plan (filed as Exhibit 10.8 to the Form 10). |
|          |   |
| 10.6+         |    | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for Directors (filed as Exhibit 10.9 to the Form 10). |
|          |   |
| 10.7+         |    | Amendment No. 1 to SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for Directors (filed as Exhibit 10.15 to the Form 10). |
|          |   |
| 10.8+         |    | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States (filed as Exhibit 10.10 to the Form 10). |
|          |   |
| 10.9+         |    | Amendment No. 1 to SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States (filed as Exhibit 10.16 to the Form 10). |
|          |   |
| 10.10+        |    | Amendment No. 2 to SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States (filed as Exhibit 10.10 to our annual report on Form 10-K for the fiscal year ended December 31, 2011, filed February 29, 2012 (the "2011 Form 10-K")). |
|          |   |
| 10.11+        |    | Employment Agreement dated as of November 30, 2009, by and among SemManagement, L.L.C., SemGroup Corporation and Norman J. Szydlowski (filed as Exhibit 10.11 to the Form 10). |
|          |   |
| 10.12+        |    | Letter Amendment dated March 18, 2010, by and among SemManagement, L.L.C., SemGroup Corporation and Norman J. Szydlowski, amending the Employment Agreement dated as of November 30, 2009 (filed as Exhibit 10.12 to the Form 10). |
|          |   |
| 10.13+        |    | Form of Severance Agreement between SemGroup Corporation and each of its executive officers other than Norman J. Szydlowski (filed as Exhibit 10.13 to the Form 10). |
|          |   |
| 10.14+        |    | Form of Amendment to Severance Agreement between SemGroup Corporation and certain of its executive officers (filed as Exhibit 10.14 to the 2011 Form 10-K). |
|          |   |
| 10.15+        |    | SemGroup Corporation Equity Incentive Plan Form of Retention Award Agreement for certain executive officers (filed as Exhibit 10.14 to the Form 10). |
|          |   |
| 10.16+        |    | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for Directors for awards granted on or after August 31, 2010 (filed as Exhibit 10.17 to the Form 10). |
|          |   |
| 10.17+        |    | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States for awards granted on or after August 31, 2010 (filed as Exhibit 10.18 to the Form 10). |
|          |   |
| 10.18+        |    | Form of 2011 Performance Share Unit Award Agreement under the SemGroup Corporation Equity Incentive Plan for executive officers (filed as Exhibit 10.1 to our current report on Form 8-K dated January 24, 2011, filed January 24, 2011). |
|          |   |
| 10.19+        |    | Form of Restricted Stock Award Agreement under the SemGroup Corporation Equity Incentive Plan for executive officers and employees in the United States during 2011 (filed as Exhibit 10.2 to our current report on Form 8-K dated January 24, 2011, filed January 24, 2011). |
|          |   |
| 10.20+        |   | Form of 2012 Performance Share Unit Award Agreement under the SemGroup Corporation Equity Incentive Plan for executive officers (filed as Exhibit 10.20 to the 2011 Form 10-K). |
|          |   |
| 10.21+        |   | Form of Restricted Stock Award Agreement under the SemGroup Corporation Equity Incentive Plan for executive officers and employees in the United States for awards granted on or after January 1, 2012 (filed as Exhibit 10.21 to the 2011 Form 10-K). |
|          |   |
| 10.22+        |   | SemGroup Corporation Short-Term Incentive Program (filed as Exhibit 10.1 to our current report on Form 8-K dated February 24, 2011, filed March 2, 2011). |
|          |   |
| 10.23+        |   | Consulting Services Agreement, effective as of February 2, 2012, by and between SemGroup Corporation and David B. Gorte (filed as Exhibit 10.23 to the 2011 Form 10-K). |
|          |   |
| 10.24         |   | Credit Agreement dated November 10, 2011, among Rose Rock Midstream, L.P., as borrower, The Royal Bank of Scotland PLC, as administrative agent and collateral agent, the other agents party thereto and the lenders and issuing banks party thereto (filed as Exhibit 10.1 to Rose Rock Midstream, L.P.’s registration statement on Form S-1, File No. 333-176260). |
|          |   |

----

|               |
|---------------|
|               |  |  |
| ExhibitNumber |    | Description |
| 10.25         |   | Second Amended and Restated Agreement of Limited Partnership of Rose Rock Midstream, L.P. (filed as Exhibit 3.1 to Rose Rock Midstream, L.P.’s current report on Form 8-K dated December 14, 2011, filed December 20, 2011). |
|          |   |
| 10.26         |   | First Amended and Restated Limited Liability Company Agreement of Rose Rock Midstream GP, LLC (filed as Exhibit 3.2 to Rose Rock Midstream, L.P.’s current report on Form 8-K dated December 14, 2011, filed December 20, 2011). |
|          |   |
| 10.27+        |   | Rose Rock Midstream Equity Incentive Plan (filed as Exhibit 10.1 to Rose Rock Midstream, L.P.’s current report on Form 8-K dated December 8, 2011, filed December 14, 2011). |
|          |   |
| 10.28+        |   | Form of Restricted Unit Award Agreement (Employees) under the Rose Rock Midstream Equity Incentive Plan (filed as Exhibit 10.3.1 to Rose Rock Midstream, L.P.’s annual report on Form 10-K for the fiscal year ended December 31, 2011, filed February 29, 2012). |
|          |   |
| 10.29         |   | Fifth Amendment to the Credit Facility, dated as of September 26, 2012 (filed as Exhibit 10.1 to our quarterly report on Form 10-Q for the quarter ended September 30, 2012, filed November 9, 2012). |
|          |   |   |
| 10.30         |   | First Amendment, dated as of September 26, 2012, to the Credit Agreement among Rose Rock Midstream, L.P., certain subsidiaries of Rose Rock Midstream, L.P., as guarantors, the lenders party thereto and The  Royal Bank of Scotland plc, as administrative agent and collateral agent for the lenders (filed as Exhibit 10.2 to our quarterly report on Form 10-Q for the quarter ended September 30, 2012, filed November 9, 2012). |
|          |   |   |
| 10.31+**      |   | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for Directors for awards granted on or after May 22, 2012. |
|          |   |   |
| 10.32         |   | Amendment No. 1 to the Second Amended and Restated Agreement of Limited Partnership of Rose Rock Midstream, L.P. (filed as Exhibit 3.1 to Rose Rock Midstream, L.P.'s current report on Form 8-K dated January 8, 2013, filed January 14, 2013). |
|          |   |   |
| 10.33+*       |   | SemGroup Corporation Equity Incentive Plan Form of Restricted Stock Award Agreement for executive officers and employees in the United States for awards granted on or after March 1, 2013. |
|          |   |   |
| 10.34+*       |   | SemGroup Corporation Equity Incentive Plan Form of Performance Share Unit Award Agreement for executive officers for awards granted on or after March 1, 2013. |
|          |   |   |
| 10.35+*       | ` | Form of Restricted Unit Award Agreement (Employees) under the Rose Rock Midstream Equity Incentive Plan for awards granted on or after March 1, 2013. |
|          |   |   |
| 21*           |   | Subsidiaries of SemGroup Corporation. |
|          |   |
| 23.1*         |   | Consent of Independent Registered Public Accounting Firm. |
|          |   |
| 31.1**        |   | Rule 13a – 14(a)/15d – 14(a) Certification of Norman J. Szydlowski, Chief Executive Officer. |
|          |   |
| 31.2**        |   | Rule 13a – 14(a)/15d – 14(a) Certification of Robert N. Fitzgerald, Chief Financial Officer. |
|          |   |
| 32.1**        |   | Section 1350 Certification of Norman J. Szydlowski, Chief Executive Officer. |
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| 32.2**        |   | Section 1350 Certification of Robert N. Fitzgerald, Chief Financial Officer. |
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| 99.1**        |   | White Cliffs Pipeline, L.L.C. financial statements presented pursuant to Rule 3-09 of Regulation S-X. |
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| 101*          |   | Interactive data files pursuant to Rule 405 of Regulation S-T: (i) the Consolidated Balance Sheets at December 31, 2012 and 2011, (ii) the Consolidated Statements of Operations and Comprehensive Income (Loss) for the years ended December 31, 2012, 2011 and 2010, (iii) the Consolidated Statements of Changes in Owners’ Equity for the years ended December 31, 2012, 2011 and 2010, (iv) the Consolidated Statements of Cash Flows for the years ended December 31, 2012, 2011 and 2010, and (v) the Notes to Consolidated Financial Statements. |

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| * | Previously filed with the Form 10-K of the Registrant filed on March 1, 2013. |

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| **     | Filed or furnished, as applicable, with this Amendment No. 1. |
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| +      | Management contract or compensatory plan or arrangement |