Summary of MARKWEST ENERGY PARTNERS L P

ITEM 7.01. Regulation FD

In accordance with General Instruction B.2 of Form 8-K, the following information in this Current Report on Form 8-K (including the exhibit) is furnished pursuant to Item 7.01 and shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to the liabilities of that section. This Current Report will not be deemed an admission as to the materiality of any information in the report that is required to be disclosed solely by Regulation FD.

On November 13, 2012, MarkWest Energy Partners, L.P. posted an updated slide presentation for investors to our website, www.markwest.com, although we reserve the right to discontinue that availability at any time. The information included with this Current Report as Exhibit 99.1 includes graphic images or slides from this presentation.

Cautionary Statements

This filing includes "forward-looking statements." All statements other than statements of historical facts included or incorporated herein may constitute forward-looking statements. Actual results could vary significantly from those expressed or implied in such statements and are subject to a number of risks and uncertainties. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we can give no assurance that such expectations will prove to be correct. The forward-looking statements involve risks and uncertainties that affect our operations, financial performance, and other factors as discussed in our filings with the Securities and Exchange Commission. Among the factors that could cause results to differ materially are those risks discussed in the periodic reports we file with the SEC, including our Annual Report on Form 10-K for the year ended December 31, 2011 and our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2012, June 30, 2012, and September 30, 2012. You are urged to carefully review and consider the cautionary statements and other disclosures made in those filings, specifically those under the heading "Risk Factors." We do not undertake any duty to update any forward-looking statement except as required by law.