A string of law firm data breaches has clients on edge about the ability of outside counsel to safeguard their confidential information. And while firms know their clients are watching, the price of effective security may be putting smaller firms at a disadvantage.

This spring marked a “watershed moment” for hacking concerns in the legal world, said James Melendres, a Snell & Wilmer partner in Los Angeles whose practice focuses on cybersecurity. The leak of 11.5 million documents from the Panamanian law firm Mossack Fonseca & Co., along with high-profile reported hacks at Cravath, Swaine & Moore and Weil, Gotshal & Manges, got clients’ attention, especially in the financial sector.