An engineering contract worth £400,000 might be billed in five stages over nine months, with 5% held back on each invoice until the defects period ends. By the time the final retention is released, the firm has carried design hours, materials and site labour for well over a year. That gap is why engineering firms look at invoice finance, and why the product needs careful matching to the way the sector bills.
How engineering firms bill and get paid
Few engineering businesses issue one invoice on delivery. Most contracts are billed against a programme:
- Milestone or stage invoices when a defined stage is reached: design approval, fabrication complete, factory acceptance test, delivery, commissioning.
- Applications for payment on construction-adjacent contracts, certified by the client's surveyor or engineer before an invoice can be raised.
- Retentions, typically 3% to 5% of each invoice, withheld until a defects period of six to twelve months ends.
- Time and materials for consultancy, maintenance and call-off work, billed monthly in arrears.
Sixty-day terms are common with large customers in energy, aerospace, defence, utilities and infrastructure; some run 90 days, and most operate a purchase order and goods-receipt process that an invoice must match before it is logged.
Work in progress (WIP): the value of design, labour and materials put into a project that has not yet been invoiced. WIP is an asset on the balance sheet but not a debt owed by a customer, so it cannot be sold to an invoice finance provider.
Where the cash-flow pressure comes from
The pressure points are structural, not a sign of poor management:
- Long design-to-delivery cycles. Months can pass before the first billable stage, with engineers and long-lead materials paid throughout.
- Lumpy stage income. A stage invoice can be 20% to 30% of the contract. If sign-off slips a fortnight, a large receipt moves; wages do not.
- Retentions that outlast the project. On £2m of annual billing, 5% retentions tie up £100,000 for a year or more.
- Supplier terms. Steel, castings and subcontractors want 30 days or pro-forma, well ahead of the customer's 60 or 90.
How invoice finance fits engineering billing
Invoice finance releases a percentage of an invoice soon after it is raised. For an engineering firm the question is which invoices a provider will treat as fundable.
Usually fundable
- Stage or milestone invoices for a stage that is complete and accepted or certified by the customer.
- Delivery invoices for equipment that has been shipped and signed for.
- Monthly time-and-materials invoices backed by approved timesheets or signed job sheets.
- Export invoices to creditworthy overseas customers, often with bad debt protection attached.
Usually not fundable
- Work in progress, however well documented.
- The retention element of any invoice, because the customer has a contractual right to withhold it.
- Applications for payment not yet certified, or invoices raised before a stage is reached.
- Invoices subject to contra charges, disputes or set-off, and deposits invoiced before work has been done.
Firms whose work is mostly certified stage billing with modest retentions tend to get a conventional facility. Those with heavy construction-style applications may be offered a lower advance rate, or pointed towards our construction factoring page.
Which structures suit engineering firms
| Structure | How it works | Engineering fit |
|---|---|---|
| Invoice discounting | Whole-ledger funding; you keep credit control, usually confidentially. | Established firms with a finance function, typically £500k+ turnover. |
| Invoice factoring | Funding plus the provider's credit control team. | Smaller firms without a credit controller. Large customers are used to paying factors. |
| Selective invoice finance | You pick which invoices or customers to fund. | Well matched to lumpy stage billing: fund the big milestones, leave the rest. |
| Bad debt protection | Add-on cover against an approved customer's insolvency. | Where one large customer or an export debtor dominates the ledger. |
Large customers, concentration and export
Engineering firms often sell to a few very large organisations: a utility, a tier-one aerospace supplier, a rail contractor. Providers like the low credit risk, which supports a higher advance rate, but they are wary of concentration. If one customer makes up 40% of your ledger, many providers apply a limit of roughly 25% to 30% and advance less against that customer, or require bad debt protection on it. Large customers also have procedures: purchase-order references, goods-receipt matching, supplier portals. A provider will want those steps completed, because an invoice the customer's system has rejected is not yet a reliable debt. Export adds currency and jurisdiction; many UK providers fund euro or dollar invoices to developed markets, usually with bad debt protection in place and proof of shipment and acceptance before an advance.
Not sure how much of your ledger would be fundable?
Tell us roughly how your contracts bill and we will explain which type of facility providers are likely to consider.
Costs and limitations for engineering firms
Charges follow the usual pattern: a service fee of roughly 0.5% to 3% of invoice value or turnover, and a discount charge on funds advanced of roughly 1.5% to 5% a year over Bank of England base rate or SONIA. Set-up, minimum monthly and audit fees may apply; our guide to invoice factoring costs explains each. Engineering-specific points:
- Lower advance rates on stage billing. Where contracts carry retentions, certification steps or set-off rights, 60% to 75% is more common than the 85% to 90% seen on simple product sales.
- Retentions excluded. The cash released is lower than the headline invoice value suggests, and on 60 or 90-day terms the discount charge runs for longer.
- Commitment. Whole-ledger facilities commonly run 12 months with three to six months' notice. If workload is project-based, a selective product avoids minimum fees in quiet months.
Illustrative example A precision engineering firm funding a milestone invoice
A machining business completes the fabrication stage of a £300,000 rail contract and raises a £90,000 stage invoice on 60-day terms with a 5% retention.
- Stage invoice value
- £90,000.00
- Less 5% retention (not fundable)
- £4,500.00
- Fundable value
- £85,500.00
- Initial advance (75% of fundable value)
- £64,125.00
- Service fee (1.5% of invoice value)
- £1,350.00
- Discount charge (approx. 8% a year on advance for 60 days)
- £843.29
- Balance released when customer pays £85,500
- £19,181.71
- Total received from facility
- £83,306.71
The £4,500 retention is paid directly to the firm when the defects period ends. The firm has paid £2,193.29, about 2.4% of the invoice, to have £64,125 roughly 58 days earlier.
Figures are illustrative estimates only and do not represent a finance offer. The discount rate assumes a 4% reference rate plus a 4% margin; actual rates, advance percentages and fees vary by provider and circumstances.
Eligibility quirks for engineering businesses
Alongside the usual criteria on our eligibility page, providers typically want evidence of acceptance for the invoices to be funded (stage certificates, delivery notes, test reports); copies of major contracts, to check retention levels, set-off rights and assignment clauses; an aged debtor report that separates disputes and retentions from fundable debt; and a view of customer spread. Some defence and infrastructure contracts prohibit assignment without consent, which a provider will usually ask you to obtain first.
Frequently asked questions
Can an engineering firm fund stage invoices with invoice finance?
Usually yes, provided the stage is complete and the customer has accepted it. A stage invoice that is really an uncertified application for payment, or that relates to work still in progress, is generally not fundable until it has been signed off.
Can retentions be funded?
Generally no. A retention is a sum the customer is entitled to withhold until a defects period ends, so it is not an unconditional debt. Most providers exclude it and advance only against the net amount currently due.
Does work in progress count as an invoice?
No. Work in progress is work done but not yet invoiced, and invoice finance only funds issued invoices for completed, accepted work. If most of your project value sits in WIP, invoice finance alone may not close the gap and more frequent stage billing may be needed.
Are large energy, aerospace or infrastructure customers good for a factoring facility?
Their credit quality is usually seen as strong, which helps the advance rate and fee. The drawbacks are long payment terms, strict acceptance procedures and concentration: if one customer is more than roughly a quarter of your ledger, many providers cap what they advance against it.
Can export invoices from engineering contracts be funded?
Often yes. Many providers fund export debtors, sometimes with bad debt protection built in because overseas credit risk is harder to assess. Expect questions about currency, contract terms, governing law and proof of shipment and acceptance.
Next steps
Split your ledger into certified invoices, retentions and unbilled work. The first pile is what a provider can fund; if it is large enough to matter, a facility is worth exploring. Before signing anything, read what happens if a customer does not pay and test your own invoices in the factoring calculator.