The usual argument over subcontractor payment terms is about fairness: should a small agency make its sub wait for the client's money, or carry the cost itself? That framing hides the number that matters. The interest on a payment gap is small. The exposure is not, because it is roughly one month of your subcontractor's invoices sitting on your balance sheet for each client who pays late, and you only find out how late when it happens.
Cash timing is not a niche worry in this sector. The 2025 Small Business Credit Survey from the Federal Reserve Banks, fielded September to November 2025, found that 56% of employer firms in its professional services and real estate group reported uneven cash flow (a category that includes collecting on receivables) as a financial challenge in the prior 12 months. This post works through what that looks like for an agency that adds a subcontractor, and where I would put the line.
What does the Federal Reserve survey say about cash flow in services firms?
The Small Business Credit Survey is an annual survey of firms with fewer than 500 employees. In the 2026 Firms in Focus chartbook on firms by industry, which reports the 2025 survey year, 56% of the 1,253 professional services and real estate employer firms named uneven cash flow as a challenge. Healthcare and education also came in at 56%, manufacturing at 57%, and retail and leisure and hospitality at 46%. The survey's note says respondents could select multiple options and that uneven cash flow includes collecting on receivables.
Two honest caveats. The group is professional services combined with real estate, so it is not a clean read on software agencies. And the survey asks whether a firm experienced the problem, not how big it was. What it does tell you is that more than half of firms in the neighbourhood of yours say the timing of cash in is a recurring headache, which is the condition you are adding a subcontractor into.
Where does the gap come from?
It comes from two clocks that start on the same day and run at different speeds. Your subcontractor invoices you monthly with terms you agreed, often 15 or 30 days. Your client pays you on the terms in your own contract, often 30, 45 or 60 days from invoice, and in practice a little later than that.
Picture a 12-person agency that brings in one subcontractor engineer on a client project. The sub invoices 18,000 dollars a month. The agency invoices the client at the end of each month, and the client's terms are net 45. Work done on a typical day is, on average, about 15 days before month end, so the client's money arrives roughly 60 days after the work. The sub, on net 15 terms, is paid about 30 days after the work. The agency is funding a 30-day gap, which is 18,000 dollars outstanding at all times.
That 18,000 dollars never goes away while the engagement runs. It only goes away when the engagement ends and the last client payment lands.
How much does carrying it actually cost?
Less than you would think, if the client pays. The Federal Reserve's H.15 release, via FRED, shows the bank prime loan rate at 7.00% on 26 October 2026. Carrying 18,000 dollars for a year at prime would cost 1,260 dollars, against 216,000 dollars of annual subcontractor spend. That is about 0.6% of the spend. A small business line of credit costs more than prime, so treat that as a floor, but even at double it the interest is not what hurts.
What hurts is the same 18,000 dollars if the client does not pay. A client that slips from 45 days to 90 adds another month of sub invoices to your exposure, 36,000 dollars in this example, and the sub still has to be paid on the schedule you agreed. The cost of a late client is not the interest. It is whether you can make payroll while waiting, and the survey's 56% suggests many firms in this position cannot comfortably.
What are pay-when-paid and pay-if-paid clauses?
A pay-when-paid clause says the agency will pay the subcontractor within some days after the agency is paid by the client. A pay-if-paid clause goes further and makes the client's payment a condition: if the client never pays, the agency owes the sub nothing. Courts and statutes treat the two differently, and the rules differ by state. I have not checked how California treats either one for software services, so this is a question for your lawyer, not a conclusion I am drawing here. Do not copy a clause from a construction template and assume it holds.
The commercial effect matters more than the legal label. A sub who is paid only when your client pays is lending you money for 60 days or more, at no interest, with the added risk of never being paid. A good engineer will either decline that, price it into the rate or give you less of their attention. If the subcontractor is a senior person you are trying to keep, a clause like that tells them how you handle risk.
So which terms would I use?
My view: pay the subcontractor on a fixed schedule and manage the exposure on the client side instead of passing it down. That does cost you the cash gap, but it is cheap, as the math above shows, and it keeps the good people.
The exposure is controlled upstream:
- Take a deposit or bill in advance. If the client pays the first month up front, the sub's first month is already funded and the gap starts at zero.
- Bill twice a month. Splitting one monthly invoice into two cuts the average wait for client cash by about two weeks, which on the example above shrinks the gap by roughly half.
- Cap the sub's exposure per client. Decide the most you will carry for any one client, for instance one month of sub spend, and stop work or pause the sub if the client's receivable passes it.
- Put a stop-work right in your client contract. You need the ability to pause when an invoice is 15 or 30 days past due, and the sub's agreement should let you give them notice to match.
- Match terms where you can. If your client pays net 30, a sub at net 15 is a smaller gap than the example. Ask what the sub needs, because many will take net 30 for a steady engagement.
For the economics of what a subcontractor costs against what you can bill, our post on white-label development economics sets out the margin side, and the paperwork guide for offshore contractors covers what you need on file before the first payment goes out.
When is a fixed pay schedule the wrong answer?
Three cases. If your agency has less than about two months of cash on hand and the client's terms are 60 days or more, a fixed schedule can sink you before the first payment arrives, so take a deposit or do not take the work. If the client has a history of slow or disputed payment, pay-when-paid with a short grace window may be the only structure you can survive, and you should tell the sub the truth about it before they start. And if the project is a one-off with a new client you have no payment history with, I would sooner price a deposit into the quote than carry the risk quietly.
This is also where an overflow partner is the wrong fit. If you cannot fund even one month of a subcontractor's invoices, adding capacity will not fix a revenue problem, it will make it larger.
What this means for your next quote
Before you quote work you plan to staff with a subcontractor, write three numbers on the page: the client's payment terms, the sub's, and one month of the sub's invoices. The third number is your exposure for that client. If you would not be comfortable if that client paid a month late, ask for a deposit, bill twice a month or say no.
If you are weighing whether to staff an upcoming project with an outside engineer, our agency overflow offer starts with a small fixed-price pilot in your own repository, so you can see the work before you commit to a monthly arrangement. We would rather tell you plainly that it does not fit than sell you capacity your cash flow cannot carry. If you would like to talk through how payment would work on your next engagement, get in touch with the project and the client's terms, and see how we build dedicated teams for the longer arrangement.
