Most leaders of large law firms say their partners are not sufficiently busy, which is hurting overall profitability, according to the results of a new survey by legal consultancy Altman Weil.

Of the 320 law firm managing partners and chairs that responded to the survey in March and April of this year, 61 percent said that overcapacity is bringing down profitability. The problem is more profound at firms with more than 250 lawyers, 74 percent of which reported that their partners’ lack of work is hurting the firm.