Borrowers assume the advance rate is a judgement about their customers. It is mostly a calculation about their own billing. Dilution is that calculation, and it explains why two companies with identical customer lists get advance rates eight points apart.
What is dilution?
Dilution is the percentage of gross sales that never converts to cash for reasons other than customer credit failure. It captures credit memos, returns, allowances, rebates, short payments, unearned discounts, warranty adjustments, and billing errors.
It is not bad debt. A customer who goes insolvent is a credit loss. A customer who pays $9,200 on a $10,000 invoice because half a pallet arrived damaged is dilution, and dilution is far more common.
How is dilution calculated?
The standard form is straightforward: total credits and non-cash reductions for a period, divided by gross sales for the same period, expressed as a percentage. Lenders normally compute it over a rolling twelve months to smooth out seasonality, and often look at the peak month as well as the average.
Lag matters. A credit issued in April against a March invoice belongs, analytically, to March. Sophisticated examiners match credits back to the originating period, which produces a higher and more honest number than a simple same-month ratio.
A worked example
A distributor with $1,000,000 of gross monthly sales:
| Item | Amount |
|---|---|
| Credit memos issued | $38,000 |
| Returns | $12,000 |
| Short payments and unearned discounts | $10,000 |
| Total dilution | $60,000 |
| Dilution rate | 6.0% |
Six percent is a workable number. It supports a conventional advance rate in the mid-eighties, because the lender needs to cover the dilution and hold a cushion on top of it.
Why does dilution set the advance rate?
Because the advance rate is the answer to one question: if we advance against this invoice today, how much of it will actually arrive? Dilution is the direct measure of the gap between the invoice face amount and the cash.
The practical convention many lenders apply is to start at 100%, subtract the dilution rate, and subtract a cushion for uncertainty. It is a rule of thumb rather than a formula, but it explains the outcomes.
| Dilution | Rough advance rate | Availability on $1.5M of eligible AR |
|---|---|---|
| 6% | 85% | $1,275,000 |
| 18% | 77% | $1,155,000 |
The same receivables, the same customers, and $120,000 less cash, purely because of how the company bills and how often it credits.
What drives high dilution?
Five things, in rough order of frequency.
- Billing before the work is fully complete, so the invoice gets adjusted later.
- Volume rebate and co-op programmes, which are contractual dilution recognised months after the sale.
- Quality and shipping problems producing routine allowances.
- Pricing errors, usually from a price list that lives in more than one system.
- Practice, not policy. Sales teams empowered to issue credits to keep customers happy, with no approval threshold.
Only the second of those is structural. The rest are process problems, which means they are fixable, and fixing them is one of the few reliable ways a borrower can improve its own terms.
What is a dilution reserve?
When dilution is high or volatile, a lender may impose a specific reserve, reducing availability by a set dollar amount or percentage on top of the advance rate. Reserves are typically imposed after a field exam finds a number worse than reported, and they appear on the borrowing base rather than in an amendment.
What triggers them, and how the examiner computes the underlying figure, is covered in the ABL field exam.
Does dilution matter in factoring specifically?
More, if anything. A factor advances against the invoice and collects from the customer, so every dollar of dilution is a dollar the factor advanced and cannot collect, recoverable only from you under a recourse arrangement. That recovery mechanism is exactly what recourse vs non-recourse factoring turns on.
It also shapes verification. A borrower with high dilution gets more invoices verified, more often, because verification is the factor’s defence against exactly this.
How do you improve it?
Measure it first, by customer and by cause, for twelve months. Most companies have never done this and are surprised by the concentration: a large share of credits usually traces to a handful of customers or one recurring process failure.
Then set a credit-memo approval threshold, fix the pricing source, and separate contractual rebates from operational credits in the reporting so the lender can see that the structural part is predictable. A dilution figure that is high but stable and explained is treated very differently from one that is merely high.
The short version
Dilution measures how much of your invoiced revenue never becomes cash for non-credit reasons, and it is the single largest input into your advance rate. It is also one of the few inputs you control directly, which makes it the cheapest place to buy yourself better terms.