Am Law 100 firms Orrick, Herrington & Sutcliffe and Pillsbury Winthrop Shaw Pittman confirmed Friday that they are in merger talks that, if successful, would create one of the world’s 20 largest firms in terms of attorney head count.

“Our firms are in exploratory discussions about a possible combination,” Pillsbury chair James Rishwain and Orrick chair Mitchell Zuklie said in a joint statement issued to The Am Law Daily. “These talks are serving to confirm the great respect our firms have for each other.” Neither Rishwain nor Zuklie returned calls seeking comment Friday, and the statement ended by saying, “We have nothing further to report at this time.”

The potential merger between Orrick and Pillsbury, news of which was first reported by Reuters on Friday afternoon, is the latest example of the ongoing trend toward consolidation in the nation’s high-end legal market. It comes as Dentons and McKenna Long & Aldridge continue their talks about a possible tie-up—a vote on that matter originally set for October 28 was recently pushed back, according to sibling publication the Daily Report—and on the heels of the announcement that Cooley will absorb Washington, D.C.–based Dow Lohnes in another large-scale combination.

Both Orrick and Pillsbury trace their roots to Gold Rush–era California, and both have seen their share of merger discussions through the years.

Pillsbury, which currently has 670 lawyers spread across 15 offices in the United States, Asia, London and Abu Dhabi, is the product of a series of combinations over the past 15 years. Originally a San Francisco–based shop known as Pillsbury, Madison & Sutro, it picked up Los Angeles­–based Lillick & McHose in 1990 and Washington, D.C.’s Cushman Darby & Cushman in 1996. In 2001, Pillsbury absorbed New York’s Winthrop, Stimson, Putnam & Roberts before rounding out its present incarnation four years later by completing a merger with D.C.–based Shaw Pittman.

Orrick, meanwhile, has considered joining forces with multiple potential partners over the years, only to stop short of striking a deal. Under the stewardship of longtime former chairman Ralph Baxter, the firm—which currently has nearly 1,100 attorneys in 25 offices around the world—pursued a merger with Silicon Valley firm Cooley Godward Kronish in 2003, but abandoned discussions in July of the year. Around the same time, Orrick considered acquiring the Venture Law Group, a firm geared toward representing Silicon Valley start-ups that went on to combine with now-defunct Heller Ehrman (VLG kept its name after the merger).

Orrick also famously held high-level discussions with Dewey Ballantine that collapsed in early 2007. The failure of that near-merger led the latter firm to enter into what ultimately proved to be its disastrous tie-up with LeBoeuf, Lamb, Greene & MacRae later that year. In September 2010, Orrick and Akin Gump Strauss Hauer & Feld confirmed that they were in “preliminary” negotiations related to a potential merger. Less than a week later, both sides said the talks were over.

Like a predator circling wounded prey, Orrick has often poached partners from firms fighting to survive. In 1998, for instance, the firm took on 40 litigators from Donovan, Leisure, Newton & Irvine after holding merger talks with the New York firm, which subsequently dissolved.