Vinson & Elkins and Latham & Watkins have landed roles on the restructuring of a joint venture between their frequent oil and gas clients Energy Transfer Partners (ETP) and general partner Energy Transfer Equity (ETE).

Dallas-based ETP and ETE said Thursday in a joint statement that the former will pay $3.75 billion in cash and stock to acquire the latter’s 60 percent stake in ETP Holdco Corp., a holding company the two companies formed last year. ETP already held the remaining 40 percent stake in ETP Holdco and will now control the holding company outright.

ETP Holdco owns equity interests of natural gas pipeline company Southern Union, which ETE acquired in 2011 for $4.2 billion, as well as oil refiner and gas station operator Sunoco, which ETP bought for $5.3 billion last year.

The transaction’s terms call for ETP to put up $1.4 billion in cash, along with $2.35 billion of its own stock, to acquire the ETP Holdco it doesn’t already own. The deal is expected to close in the second quarter of this year.

ETP and ETE said in a statement that the deal would "simplify [the companies'] structures and optimize their asset portfolios" in line with other recently announced structural changes involving the Southern Union assets. ETP and ETE sold Southern Union’s natural gas gathering systems to affiliate company Regency Energy Partners last month for $1.5 billion, two months after announcing a plan to sell two of Southern Union’s local distribution companies to The Laclede Group in a $1 billion deal.

Both Vinson and Latham have long histories with the Energy Transfer general partners. As The Am Law Daily has previously reported, Thomas Mason, a former partner at both Andrews Kurth and Vinson, has served as Energy Transfer’s general counsel since 2007. Vinson’s past work for the companies includes representing ETE in 2012 when it and ETP (which was represented at the time by Andrews Kurth), acquired an interest in Regency Energy for $300 million.

The same year, William Finnegan IV, himself a former Andrews Kurth and Vinson partner and frequent Energy Transfer adviser, left Vinson with a handful of partners to open Latham’s Houston office. Since then, Latham has worked on a number of Energy Transfer transactions, including the purchases of both Southern Union and Sunoco. Latham also advised ETE on its sale of Southern Union assets to Regency in February and worked with both ETE and ETP on the Laclede deal last December.

The Vinson team advising ETP on the purchase of the remaining ETP Holdco stake includes corporate partners David Oelman and William "Matt" Strock, both in Houston. Tax partner John Lynch is also advising, along with antitrust partners William Vigdor and Cathy Lewis. The Vinson associates working on the deal are Lande Spottswood, Brett Riesenfeld, and Ryan Carney.

Houston-based Latham M&A partners Finnegan and Sean Wheeler are leading that firm’s team, which also includes tax partner C. Timothy Fenn. The Latham associates working on the matter are Debbie Yee, Cephas Sekhar, and Eric Matuszak.