The dropdown is the partnership's first acquisition since its initial public offering in August 2013.
Eagle Rock’s midstream assets include approximately 8,100 miles of gathering pipeline and more than 800 million cubic feet per day (MMcf/d) of processing plants.
Williams now owns 100% of the general partner and about 50% of the limited partner units in Access Midstream Partners.
Pinto Energy is developing an estimated 2,800 bbl/d plant near the Port of Ashtabula, Ohio.
Tulsa, Okla.-based Rose Rock now owns a 51% interest in White Cliffs Pipeline.
Enbridge Partners will own a 48.4% limited partner interest in Houston-based Midcoast Operating.
The assets will likely contribute about $15.4 million in EBITDA during their first full year.
The transaction is estimated to be worth a total of $500-600 million.
Dallas-based Southcross will gain roughly one-third of TexStar’s assets.
CONE Gathering LLC will provide midstream services for their jointly-owned Marcellus acreage.
TransMontaigne is a terminaling and transportation company based in Denver.
Summit intends to invest $1.2 billion in Ohio Gathering through 2018.