Yes. Under ABA Model Rule 1.15 (Safekeeping Property), a lawyer must hold property of clients or third persons separate from the lawyer’s own property. Client funds must be kept in a separate trust account maintained in the state where the lawyer’s office is situated, or elsewhere with the client’s or third person’s consent. Advance legal fees and expenses are deposited into that account and may be withdrawn only as fees are earned or expenses incurred.
In practice, nominal or short-term client funds are often pooled in an IOLTA (Interest on Lawyer Trust Accounts) account under state rules, while larger or longer-held amounts typically go into a separate interest-bearing account for the client. Exact IOLTA requirements vary by state.