Norton Rose Fulbright and Kirkland & Ellis have emerged as the top mergers and acquisitions (M&A) legal advisers in the oil and gas sector by value and volume, respectively, in the first half of 2025 (H1 2025), according to the latest league table published by GlobalData, a data and analytics company.

GlobalData’s Deals Database revealed that Norton Rose Fulbright secured the top spot in terms of deal value, advising on transactions worth $27.1bn.

Kirkland & Ellis led in terms of volume, advising on 18 deals.

GlobalData lead analyst Aurojyoti Bose said: “Kirkland & Ellis was the top adviser by volume in H1 2024 and retained the leadership position by this metric in H1 2025 as well. Apart from leading by volume in H1 2025, Kirkland & Ellis also held the second position by value.

“Meanwhile, Norton Rose Fulbright registered a massive jump in the total value of deals advised by it during H1 2025 compared to H1 2024 due to involvement in big-ticket deals. Resultantly, its ranking by value took a significant leap from 64th position in H1 2024 to the top position in H1 2025.

"Four of the five deals advised by Norton Rose Fulbright during H1 2025 were billion-dollar deals, which also included a megadeal valued at more than $10bn.”

Kirkland & Ellis also claimed second position by value, advising on deals amounting to $24.1bn, followed by Vinson & Elkins at $23.3bn, Simpson Thacher & Bartlett at $21.3bn, and Blake Cassels & Graydon at $16.7bn.

In terms of deal volume, Vinson & Elkins took second spot with 14 deals, while Gibson, Dunn & Crutcher advised on eight, Akin Gump Strauss Hauer & Feld on seven, and Simpson Thacher & Bartlett on six transactions.

GlobalData’s league tables are based on the real-time tracking of thousands of company websites, advisory firm websites and other reliable sources available on the secondary domain. A dedicated team of analysts monitors all these sources to gather in-depth details for each deal, including adviser names.

To ensure further robustness to the data, the company also seeks submissions of deals from leading advisers.