Which law firms have the strongest brands in the United States, the world’s largest legal market? According to a study released this week by Acritas, the brand research company, Skadden, followed by Jones Day, Kirkland & Ellis, Sidley Austin, and Wachtell, lead the big-firm pack.

Acritas compiled its list based on answers to phone interviews with 902 clients, 667 headquartered in the U.S. These are big clients: 58 percent report revenues of at least $1 billion. They answered the following inquiries: