If you're not worried about the Big Four, you should be. That's the message many legal industry watchers have been sharing with law firm leaders, and one that's taken on added resonance with last week's announcement that Deloitte UK will ally with U.S. immigration law firm Berry Appleman & Leiden. Seyfarth Shaw the burgeoning market for alternative legal services providers Eversheds Sutherland Guberman Garson There's a lot about the immigration practice that makes sense: the ability to think about efficiencies, technology and high volume," Poor said. "Those are characteristics that play right to the Big Four's strengths." Looking for New Niches It's very smart on their part," said James Jones, who directs the Georgetown University center. "Under practice rules in the U.S., they can't acquire a law firm, but they can in the U.K. and other countries." hey've managed to develop some form of a relationship that everyone's realized is good for their business," Poor said. "It shows that in some ways, you can continue to thread that needle." I think it's telling that private equity is an area that they're clearly competing in in some international money centers," he said. "The extent to which they take market share in those high-rate areas, that's really going to sting for international firms." Advantages There's a lot of stuff that people like Deloitte and the other Big Four firms and other nontraditional service providers can do without stepping over that line into the unauthorized practice of law," he said.