A retainer invoice is a bill a professional sends before starting work, requesting an upfront deposit that secures their availability and creates a pool of funds they can draw from as they earn fees. It reverses the usual billing sequence: money moves first, work follows. The arrangement is most common with lawyers but also shows up in consulting, accounting, and creative work.
How It Differs From a Regular Bill
Timing is the whole difference. A standard invoice lists work already done and asks to be paid for it. A retainer invoice asks for payment before any work begins. The deposit sits in a holding account, and the professional bills against that balance over time.
One consequence often gets missed. Money you pay on a retainer invoice is not immediately spent. Until the professional earns the fee by doing actual work, that money still belongs to you. That single fact shapes how the funds are stored, what you can ask for back, and what happens if the relationship ends early.
What Should Be on the Invoice
A retainer invoice usually accompanies an engagement letter or fee agreement, and it should carry enough detail for you to check it against what you negotiated. Expect to see:
- The firm’s legal name, address, and contact information.
- Your full legal name or business name and billing address.
- A unique invoice number for tracking.
- A matter description tying the deposit to a specific case or project, so funds are not applied to the wrong work.
- The retainer amount, which varies with the complexity of the matter and the professional’s hourly rate.
- Payment instructions, including wire details or a mailing address. Some firms accept credit cards, though processing fees may apply and should be disclosed separately.
- A payment deadline, typically before work begins.
The fee agreement matters as much as the invoice. It should spell out the hourly rate, which expenses you are responsible for, and the billing schedule. Under ABA Model Rule 1.5, lawyers must communicate the basis of their fee to the client, preferably in writing, before or shortly after starting work. If anything on the invoice does not match what you discussed, flag it before you pay.
Where Your Money Is Held
Once you pay, your money does not go into the firm’s regular bank account. Under ABA Model Rule 1.15, lawyers must deposit advance fee payments into a separate client trust account and can only withdraw funds as they earn them or incur expenses on your behalf. This is not a best practice. It is an ethical requirement enforced by state bar associations.
Most lawyers use an Interest on Lawyers’ Trust Account, or IOLTA. These pooled accounts hold small or short-term client deposits together, and the interest earned goes to the state’s IOLTA program, which funds legal aid. You will not see interest income from your deposit.
The point of the arrangement is separation. Your retainer money cannot be mixed with the firm’s operating funds, used to pay the firm’s rent, or cover another client’s expenses. Commingling client funds with firm money is one of the most common reasons lawyers face discipline, and state bars regularly suspend or disbar attorneys who fail to keep client money segregated, even when the commingling is careless rather than intentional.
Types of Retainer Arrangements
Not all retainers work the same way, and the structure affects how your money is handled and whether any of it comes back to you. The invoice itself may not spell this out, so read the fee agreement.
Advance Fee Deposit
The most common arrangement. You pay a deposit, the professional bills against it at their hourly rate, and any unused portion is returned when the engagement ends. When people say “a retainer,” this is almost always what they mean.
Evergreen Retainer
An evergreen retainer requires you to maintain a minimum balance in trust throughout the engagement. The fee agreement sets two numbers: the initial deposit and a replenishment threshold, often around half the original amount. When the balance falls to that threshold, you receive a notice to top it back up. This is common in family law and litigation, where the pace of work is unpredictable.
True Retainer or Availability Fee
A true retainer is different in kind. You are not paying for specific work. You are paying for the professional’s availability over a set period, compensating them for turning away other clients. Because the fee is earned the moment you pay it, a true retainer may not be refundable. Many jurisdictions prohibit lawyers from labeling an advance fee deposit as “non-refundable” when it is really payment for work that has not been done yet. If your agreement uses the phrase “non-refundable retainer,” make sure you understand which of these two things you are actually buying.
How the Drawdown Works
After you fund the retainer, you should receive regular billing statements showing how the deposit is being consumed. Each statement lists tasks performed, time spent, the hourly rate applied, and the dollar amount deducted from your balance. The schedule is whatever your fee agreement sets, often monthly.
As the professional earns fees, they transfer the corresponding amount from the trust account to their operating account. That transfer is the only point at which the money stops being yours. Rule 1.15 requires withdrawals only after fees are earned or expenses actually incurred.
Expenses like court filing fees, expert witness costs, and document production are usually drawn from the retainer as well, unless the agreement says otherwise. In litigation, these add up fast. Ask at the outset whether your retainer covers both fees and expenses or just professional time.
If the Retainer Runs Out
When the balance hits zero before the work is done, the professional will ask you to replenish. Under an evergreen arrangement, that request comes before the balance reaches zero. Under a standard advance deposit, you may not hear about it until the account is empty.
Ignoring a replenishment request has consequences. Under ABA Model Rule 1.16, a lawyer may withdraw from your case if you substantially fail to meet your financial obligations after reasonable warning. In active litigation, withdrawal also requires court approval, and the court will weigh whether leaving you mid-case would cause serious harm. Outside litigation, a professional who has warned you and heard nothing back can ethically stop working.
Refunds and Fee Disputes
Your right to a refund of unearned retainer funds is well established. When the attorney-client relationship ends for any reason, Rule 1.16 requires the lawyer to refund any advance payment of fees that have not been earned. The refund must be prompt, and the lawyer must also take reasonable steps to protect your interests, including giving you time to find replacement counsel and turning over your file.
If you disagree with how much of the retainer was earned, the lawyer is supposed to hold the disputed amount in trust until the disagreement is resolved. Pocketing disputed funds is itself an ethical violation.
Most state bar associations run fee arbitration programs for disputes over legal fees. These are faster and cheaper than suing your lawyer. The ABA has published model rules for fee arbitration that many states have adopted in some form. If you believe you were overcharged or that your retainer was improperly consumed, your state bar’s fee dispute program is the first place to go.
Tax Reporting
Retainer payments create tax obligations on both sides that are easy to miss.
For the Professional
The IRS treats advance payments for services as taxable income in the year they are received, not the year the work is performed, for professionals using the cash method of accounting. A lawyer who collects a retainer in December but does not start the work until February still reports that income for the earlier year. If the professional later refunds unearned fees in a different tax year, they can deduct the repayment in the year it is made.
For the Client
If you pay a retainer in the course of your trade or business and your total payments to that attorney reach $600 or more during the calendar year, you must file a Form 1099-NEC reporting the payment. Personal legal fees paid by individuals for non-business matters, such as a divorce or estate plan, do not trigger a 1099 filing requirement.
Business clients can generally deduct legal fees that are ordinary and necessary expenses of the business. The deduction applies in the tax year the expense is incurred, which for a retainer means the portion corresponding to work actually performed that year, not necessarily the year you funded the account.