MarkWest Energy Partners, L.P. and its subsidiary MarkWest Energy Finance Corporation announced the closing of a public offering of $1,200,000,000 in aggregate principal amount of 4.875% senior unsecured notes due 2025.

The Partnership expects to receive net proceeds from the offering, after deducting underwriting discounts, commissions and offering expenses, of $1,175,068,000. The Partnership intends to use the net proceeds from the offering to fund the payments it will make upon the settlement of its pending tender offers for any and all of the Issuers’ outstanding 6.75% senior unsecured notes due 2020, 6.5% senior unsecured notes due 2021 and 6.25% senior unsecured notes due 2022. Any amounts required to make the payments necessary at settlement of the Tender Offers that are not funded by the net proceeds from the offering will be funded partly by cash on hand, with the remainder to be funded through borrowings under the Partnership’s revolving credit facility.

Any remaining net proceeds from the offering will be used to redeem or otherwise acquire any 2020 Notes, 2021 Notes or 2022 Notes not acquired by the Partnership in the Tender Offers or to provide additional working capital for general partnership purposes.

Wells Fargo Securities, Barclays Capital Inc., Citigroup Global Markets Inc., Goldman, Sachs & Co., J.P. Morgan Securities LLC, BofA Merrill Lynch, Morgan Stanley & Co. LLC, RBC Capital Markets, LLC, SunTrust Robinson Humphrey, Inc., U.S. Bancorp Investments, Inc. and UBS Securities LLC are acting as joint book-running managers for the offering of the 2025 Notes.