Access Midstream Partners, L.P. (NYSE: ACMP) (“ACMP”) today announced that the record date and distribution date have been set for ACMP’s previously announced subdivision of (i) each common unit of ACMP (the “ACMP Common Units”) into 1.06152 ACMP Common Units and (ii) each Class B unit of ACMP (the “ACMP Class B Units” and together with the ACMP Common Units, the “ACMP Units”) into 1.06152 ACMP Class B Units (the “Pre-Merger Unit Split”). The Pre-Merger Unit Split is being effected in accordance with the Agreement and Plan of Merger, dated as of October 24, 2014 (the “Merger Agreement”), among ACMP, the ACMP General Partner, Williams Partners L.P. (“Williams Partners”), Williams Partners GP LLC (the “WPZ General Partner”), and VHMS LLC (“Merger Sub”), pursuant to which WPZ will merge with Merger Sub and become a wholly owned subsidiary of ACMP (the “Merger”). The consummation of the Pre-Merger Unit Split and the Merger are each contingent upon the satisfaction or waiver of specified conditions set forth in the Merger Agreement. The Pre-Merger Unit Split will be effected prior to the closing of the Merger such that holders of Williams Partners partnership interests will not participate in the Pre-Merger Unit Split with respect to the Williams Partners partnership interests they hold.

The record date for the Pre-Merger Unit Split will be January 30, 2015 (the “Record Date”). The distribution of the ACMP Units in connection with the Pre-Merger Unit Split is expected to occur prior to the market open on February 2, 2015 (the “Distribution Date”). The transfer agent will not distribute any fractional ACMP Units in connection with the Pre-Merger Unit Split. Each fractional ACMP Unit will be rounded to the nearest whole ACMP Unit (and a 0.5 ACMP Unit will be rounded to the next higher ACMP Unit).

Holders of ACMP Units on the Record Date are not required to take any action in order to receive ACMP Units in connection with the Pre-Merger Unit Split. ACMP unitholders entitled to receive ACMP Units in connection with the Pre-Merger Unit Split will either receive a book-entry account statement reflecting their ownership of ACMP Units or their brokerage account will be credited for the ACMP Units.

Trading in Shares of ACMP Common Units Between the Record Date and the Distribution Date

ACMP Common Units will continue to trade “regular way” on the New York Stock Exchange (the “NYSE”). As a result of the related “due bill” trading procedures, persons acquiring ACMP Common Units in the market on January 28, 2015 and through the Record Date will be entitled to receive ACMP Common Units issued in connection with the Pre-Merger Unit Split. The “ex-distribution” date for the Pre-Merger Unit Split will be February 2, 2015.

The closing of the Merger is expected to occur subsequent to the market open on the Distribution Date, and following the closing of the Merger, ACMP Common Units and Williams Partners common units are expected to continue trading on the NYSE during normal trading hours throughout the remainder of the Distribution Date. ACMP unitholders are encouraged to consult with their financial advisors regarding any trades with respect to their ACMP Common Units prior to the Distribution Date and the trading policies and practices of the NYSE relating to the Pre-Merger Unit Split.

Following the closing of the Merger, it is anticipated that ACMP will change its name to Williams Partners L.P. and that the ACMP Common Units will trade on the NYSE under the symbol “WPZ.”

About Williams, Williams Partners and Access Midstream Partners

Headquartered in Tulsa, Okla., Williams (NYSE: WMB) is one of the leading energy infrastructure companies in North America. It owns controlling interests in both Williams Partners L.P. and Access Midstream Partners, L.P. through its ownership of 100 percent of the general partner of each partnership. Additionally, Williams owns approximately 66 percent and 50 percent of the limited partner units of Williams Partners L.P. and Access Midstream Partners, L.P., respectively.

ACMP owns and operates natural gas midstream assets across nine states, with an average net throughput of approximately 3.9 billion cubic feet per day and more than 6,495 miles of natural gas gathering pipelines. ACMP’s operations are focused on the Barnett, Eagle Ford, Haynesville, Marcellus, Niobrara and Utica Shales and the Mid-Continent region of the U.S.

Williams Partners owns and operates both on-shore and offshore assets of approximately 15,000 miles of natural gas gathering and transmission pipelines, 1,800 miles of NGL transportation pipelines, an additional 11,000 miles of oil and gas gathering pipelines and numerous other energy infrastructure assets. Williams Partners’ operated facilities have daily gas gathering capacity of approximately 11 billion cubic feet, processing capacity of approximately 7 billion cubic feet, NGL production of more than 400,000 barrels per day and domestic olefins production capacity of 1.95 billion pounds of ethylene and 90 million pounds of propylene per year.

For more information about Williams, Williams Partners and ACMP, visit www.williams.com, www.williamslp.com or www.accessmidstream.com.

Forward-Looking Statements

Portions of this press release may constitute “forward-looking statements” as defined by federal law. Although ACMP believes any such statements are based on reasonable assumptions, there is no assurance that actual outcomes will not be materially different. Any such statements are made in reliance on the “safe harbor” protections provided under the Private Securities Reform Act of 1995. Additional information about issues that could lead to material changes in performance is contained in ACMP’s annual reports and other filings with the Securities and Exchange Commission.