Expenses are rising faster than revenue at the nation’s largest law firms, and those in charge of running those firms are finding it harder to manage the imbalance, according to a recent survey conducted by Wells Fargo’s Legal Specialty Group.

The survey—one of three that Wells Fargo conducts on the state of the legal industry each year by polling law firm clients—gathered input from 115 firms on a variety of performance-related categories covering the period from January through June. Of the responding firms, more than half came from the Am Law 100, according to Wells Fargo, with the rest falling into the Am Law Second Hundred.