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UPDATE: 6/10/14, 8:48 a.m. EDT. The names of the lawyers from Porter Hedges have been added to the seventh and eighth paragraphs of this story.

Two companies linked to billionaire Aubrey McClendon—one of the foremost backers of the so-called U.S. shale gas revolution—made big moves in the energy space Monday. And a handful of large law firms have landed roles on both matters.

Chesapeake Energy Corp., the Oklahoma City-based oil and gas company cofounded by McClendon, who was forced to retire as its CEO last year, saw its board of directors approve Monday a plan to shed $1.1 billion in debt by spinning off its oilfield services unit later this month.

The new publicly traded company will be called Seventy Seven Energy. Wachtell, Lipton, Rosen & Katz corporate partner David Katz is advising Chesapeake’s board on the plan, while the company itself has retained Baker Botts and Oklahoma’s McAfee & Taft. Chesapeake, which last week sold some transportation assets to Rose Rock Midstream LP for an undisclosed sum, has sought to streamline its operations following last year’s change in management.

As for McClendon, whose tenure at Chesapeake was marred by allegations of excessive spending and conflicts of interest (an investigation ultimately cleared him of wrongdoing in mixing personal loans with corporate finances), he started American Energy Partners LP just down the street from his old corporate headquarters.

Oklahoma City-based AEP, whose general counsel is Robert Kelly, almost immediately began acquiring oil and gas leases to capitalize on the shale boom that McClendon has been the face of in recent years. In January, an AEP subsidiary paid $924 million to struggling Hess Corp. for 74,000 acres of assets in Ohio’s Utica shale formation. AEP’s market value hit $5 billion by February.

On Monday, AEP announced another trio of shale acreage acquisitions totaling some $4.25 billion. Sullivan & Cromwell, Houston’s Porter Hedges and Oklahoma City’s Commercial Law Group P.C. are advising AEP on the transactions, according to a press release. The Commercial Law Group has been a longtime legal adviser to McClendon and Chesapeake, having counseled the latter on its $4.75 billion sale of assets in the Fayetteville shale formation in 2011, according to our previous reports.

Last year Porter Hedges picked up energy partner Jeremy Mouton in Houston from the Commercial Law Group. Mouton and fellow corporate partner Corey Brown, who joined Porter Hedges in 2011, are currently advising AEP along with associates Deborah Ko, H. McCaleb Marshall and Brian Rose. The group is working on a $2.5 billion slice of the deal that will see AEP acquire 63,000 net acres of oil and gas properties in Texas’ Permian Basin owned by EnCap Investments, a subsidiary of Denver-based Enduring Resources.

Another Porter Hedges team, led by Mouton, Ko, Marshall and associate R. Dennis Ng, is advising AEP on its payment of another $1.75 billion to East Resources Inc. and an unidentifed private buyer to acquire an additional 75,000 net acres in the Marcellus and Utica shale formations.

Latham & Watkins, whose opening of a Houston office in 2010 was the subject of a recent feature story in The American Lawyer, has taken the lead for Enduring on its deal with AEP. Corporate partners Michael Darden and Michael Dillard, oil and gas partner Michael King, finance partner Catherine Ozdogan, tax partner C. Timothy Fenn, environmental partner Joel Mack, antitrust counsel Sydney Smith and associate James Robertson are working on the matter for Latham. The firm, which also advised Hess on its shale sale to AEP earlier this year, has previously done work for Enduring.

Baker Botts is advising the sellers led by East Resources on the second transaction with AEP. As noted above, Baker Botts is also counseling Chesapeake on its spinoff of Seventy Seven Energy. Taking the lead on that matter are Baker Botts capital markets partner Hillary Holmes, M&A partner Derek Green, tax partner Chad McCormick, finance partner Shalla Prichard, employee benefits partner Mark Bodron, environmental partner J. Scott Janoe and associates Rachael Lichman, Aaron Pinegar and Katie Ryan.

Last year Chesapeake named former Bracewell & Giuliani litigation partner Patrick Craine to serve as its new chief compliance officer, reporting to the company’s newly installed general counsel James Webb. Chesapeake’s in-house legal department was caught up in the company’s investigation into McClendon, according to sibling publication Corporate Counsel. (Chesapeake’s former in-house legal chief Henry Hood currently works as a consultant to the oil and gas industry.)

The audit committee of Chesapeake’s board of directors hired Locke Lord to review loans made to McClendon, while Wachtell served as corporate governance and M&A counsel to the company. McClendon was advised in the probe by Duane Morris litigation partner Marvin Pickholz, a former assistant director of enforcement at the SEC.