Allen & Overy and O’Melveny & Myers have held talks about a potential combination, according to two sources briefed on the matter.

If a merger deal is finalized between both firms, it would create a 3,000-lawyer global giant with roughly $2.8 billion in combined gross revenue. Details of the talks, to date, have been contained to only a small number of senior figures, although Allen & Overy partners were told in January that the Magic Circle firm was in talks with several U.S. firms about a potential combination.

A former O’Melveny & Myers partner said that the Am Law 100 firm is in “deep” discussions with Allen & Overy. Firm leaders have traveled to meet one another and have discussed titles of the combined firm, the source said. For its part, O’Melveny & Myers denied that any deal was imminent.

“We have no plans to merge and never have,” said a spokesman for the Am Law 100 firm, which has its roots in Los Angeles and in 2002 acquired O’Sullivan, a New York-based shop specializing in private equity work.

In its own statement, Allen & Overy acknowledged that is has approached other firms about potential deals.

“While we have said for several years that we are open to considering a merger with the right partner in the U.S., we talk to many firms in many countries all of the time and we do not comment on market speculation and rumors regarding any particular firm,” the firm said.

Allen & Overy has held talks about potential tie-ups with a number of U.S. firms in recent years, including Arnold & Porter before that firm finalized another combination with Kaye Scholer, said a source familiar with those negotiations. The London-based legal giant has been open about its desire to increase its presence in the U.S., where many large U.K. firms have sought to bolster their presence within the past two decades.

“We have to have critical mass out there from both an offensive and defensive position,” said one Allen & Overy partner, who requested anonymity when talking about firm affairs. “I definitely see the case for us to do something.”

Allen & Overy senior partner Wim Dejonghe and managing partner Andrew Ballheimer, both of whom prioritized the need for U.S. expansion when running for their current roles in 2016, are leading the talks for the firm.

O’Melveny & Myers, which has been led since 2011 by New York-based chairman Bradley Butwin, has been actively exploring its growth options during the past year. The New York Law Journal reported in December that O’Melveny & Myers had held preliminary merger talks with Willkie Farr & Gallagher, but the discussions did not get far. Both firms denied that they had held merger talks.

In 2017, O’Melveny & Myers saw its gross revenue rise slightly, to $738 million, while profits per equity partner were roughly $2 million. Allen & Overy shares similar profitability, with partners earning roughly $2.1 million for fiscal 2016-17, a year in which the Magic Circle firm saw double-digit growth in several key financial metrics.

Allen & Overy has two existing U.S. offices in New York and Washington, D.C., the latter of which was launched in 2011 by a team of former O’Melveny & Myers partners. Allen & Overy has made a number of lateral hires in the U.S. in recent years, including a group of finance partners who joined the firm in 2016 from Proskauer Rose and White & Case. Scott Zemser, one of those hires, served as global leveraged finance co-head at Allen & Overy until he left the firm earlier this year to join Mayer Brown in New York.

O’Melveny & Myers has 660 lawyers working out of 15 offices, including seven in the U.S., six in Asia and two in Europe. O’Melveny & Myers’ presence in Asia has taken a hit in recent years, as head count had been roughly halved through partner departures, although the firm has sought to restock some of its offices in the region with lateral hires. O’Melveny & Myers has watched its finances recover during the past three years following a decline that halted in 2014. The firm’s gross revenue has still not returned to what it was in 2010, or in 2012, when O’Melveny & Myers had its best year with $818.5 million in gross revenue and partner profits topped $2 million for the first time.

Within the past decade, O’Melveny & Myers has not caught up to some of its peer firms that began in Los Angeles, such as Gibson, Dunn & Crutcher, Latham & Watkins and Paul Hastings. For instance, between 2006 and 2016, O’Melveny & Myers partners saw their profits increase 20 percent. But at Gibson Dunn that increase was 87.1 percent, at Latham 65 percent and at Paul Hastings profits were up 62 percent during that same timeframe, according to data gleaned by ALM Intelligence. Like many other Am Law 100 firms, O’Melveny & Myers has been unable to match the incredible growth rates put forth by Kirkland & Ellis and Latham. (The latter raided O’Melveny & Myers for a high-profile group of entertainment lawyers in late 2014.)

In March, George Davis, a former member of O’Melveny & Myers’ executive committee and co-chair of the firm’s global restructuring practice, left its New York office to become the new global co-chair of restructuring, insolvency and workouts at Latham. Danielle Gray, a former Obama administration official who returned to O’Melveny & Myers in 2014, also recently left the firm to become the new chief legal officer for Blue Cross and Blue Shield of North Carolina.

O’Melveny & Myers could see more partner exits soon. Richard Shutran, who arrived at the firm in 2012 following the collapse of Dewey & LeBoeuf, where he served as co-chair of the now-defunct firm’s corporate department and chair of its global finance practice, is in talks to join Winston & Strawn, said a source familiar with the potential move. Shutran could not be reached for comment Friday.

A union between O’Melveny & Myers and Allen & Overy would place the firm near the top of The American Lawyer’s Global 100 rankings, just below Kirkland and Latham, both of which broke the $3 billion mark for gross revenue in 2017, and ahead of DLA Piper, which took in $2.73 billion last year.

David Morley, the predecessor for Dejonghe as Allen & Overy’s senior partner, once admitted that he would have liked the firm to have made more progress in the U.S. during his leadership tenure. In a video interview with sibling publication Legal Week in 2016, Morley predicted that his successor would lead the charge for the big British firm in the U.S. and said that large U.K. firms needed to rethink their approach and be more open to cross-border combinations.

That sentiment is shared by at least one former Allen & Overy partner in the U.S., where the Magic Circle firm picked up three Paul Hastings finance partners last year.

“There was always a gap between the economic and cultural quality of the type of firm you can attract and the quality of the firm that Allen & Overy partners would be happy to call a merger equal,” the former partner said. “That gap has narrowed in the last year—[Allen & Overy] turned in a very strong year and remains a well-regarded firm. The number of potential quality merger partners has increased as a result.”

Any deal between Allen & Overy and O’Melveny & Myers would be the latest in a series of sizeable law firm combinations. Three deals involving at least one Am Law 100 firm closed this week, while several other smaller unions were announced involving large firms in New York, Pittsburgh and Vancouver.

Kent Zimmermann, a consultant with law firm advisory outfit the Zeughauser Group who helped close three large deals this week, including the cross-border union between Bryan Cave and Berwin Leighton Paisner, said the merger mania has created a buzz in the U.S. and U.K. legal markets and captured the attention of law firm leaders on both sides of the Atlantic.

“I have experienced a recent increase in interest on the part of some leaders of Magic Circle and Silver Circle firms in assessing the U.S. market,” said Zimmermann, who spoke Friday from London but is uninvolved in the talks between Allen & Overy and O’Melveny & Myers.

Zimmermann added that some of these British firms are exploring all options, including growing through lateral hires, large group acquisitions and possibly combining with another U.S. firm, if the right fit exists.

Additional reporting by Meghan Tribe.