As PricewaterhouseCoopers prepares to formally launch a U.S. legal services business, a new study has warned that law firms need to become more efficient and develop alternative services in areas such as technology and process management in order to counter the growing threat posed by the Big Four accounting firms.

The report, by ALM Intelligence, said that law firms should “prepare for a significant increase in competition”—particularly if the Big Four start targeting more higher-value work. And they will need to look at changing their staffing models to help reduce costs, the report said.

Law firms should also consider forming managed legal services partnerships with the Big Four, the report added. U.K. Magic Circle firm Allen & Overy last year teamed up with Deloitte to launch a technology product that helps banks deal with complex new derivatives regulations.