Construction Invoice Factoring and Retainage: Getting Paid Before the Owner Pays

By MercFinancial · Published 2026-10-21

Construction invoice factoring lets a contractor sell a verified progress billing and receive most of its value within days, the balance when the owner pays. Why general factors decline it, what construction factors need, and the cost.

Construction invoice factoring lets a contractor sell a verified progress billing to a factor and receive most of its value within days, with the balance, less the factor's fee, paid when the owner or general contractor pays. It is a specialty within factoring because a construction receivable is unlike any other: billed on progress rather than delivery, subject to retainage, conditioned on lien waivers, exposed to back charges and offsets, and often payable only when the party above has been paid. General factors decline it. Construction factors price it.

This guide explains why construction factoring is its own trade, what a construction factor requires before it buys a billing, how the cost works on an illustrative draw, what happens to retainage and who will advance against it, the alternatives that fit when factoring does not, and how MercFinancial places a factoring request among its contractor funding sources.

A factor does not lend to the contractor. It buys the owner's promise to pay, and it prices how good that promise is.

Why construction factoring is a specialty

Factoring in most industries is simple: a delivered product, an invoice, a customer who owes it, and a factor that buys the invoice and collects it. A construction progress billing breaks every part of that. The work is partly done, so the amount owed depends on an inspection or an architect's certification. The owner holds back retainage, so the invoice is never paid in full on its own. Payment is conditioned on lien waivers, and the waiver the contractor signs to get paid can release the lien rights that protect the factor. Back charges, offsets and unapproved change orders reduce the amount paid after the billing was issued. And a pay-when-paid clause makes the general contractor's payment depend on the owner, two steps removed from the factor.

General factors decline the industry for those reasons, and invoice factoring versus purchase order financing describes the baseline product they are declining from. Construction factors underwrite each complication: they verify the billing with the payer, exclude retainage, manage the waiver exchange, and price the time the owner takes. The result costs more than ordinary factoring and funds receivables no bank line will touch, for the reasons in why banks decline contractors.

What a construction factor requires before it buys a billing

A construction factor's file is built around the payer and the job, and the contractor's own financials come last.

How the cost works, with an illustrative draw

A factor's price has two parts: the advance rate and the fee. The advance is the share of the verified billing paid up front, commonly within the 70 to 90 percent range that factoring runs across industries and often toward the lower end on construction because of offsets and retainage. The fee is quoted per period the billing stays unpaid, typically per 30 days or in shorter increments, and is deducted from the reserve when the payer pays. A slow owner costs more than a prompt one, which is why the factor underwrites the payer more closely than the contractor.

Two features of the example matter beyond the arithmetic. The factor earned its fee on the whole billing, not on the advance, which is standard. And the contractor's cost follows the payer's speed, so a subcontractor working for a prompt general contractor pays less than one working for a slow one, with the same factor.

Retainage: who holds it, who advances against it

Retainage is the share of every progress billing the owner holds until substantial completion or final acceptance, and on commercial work it commonly runs 5 to 10 percent of each billing. In Texas, retainage held by an owner is tied to lien rights under Chapter 53 of the Property Code, and a subcontractor's claim on it depends on notices filed on time. For a factor the retainage is a receivable with no fixed date, exposed to the punch list, to back charges and to the owner's willingness to close out, so nearly all factors exclude it from the advance and some exclude it from the fee calculation as well.

A smaller set of specialty lenders will advance against retainage on jobs at or near completion, where the remaining risk is the close-out rather than the work. They underwrite the owner, the status of the punch list and the contractor's record of collecting retainage on past jobs, and they price the uncertainty. For a contractor with a large retainage balance across several jobs that advance can be meaningful, and it is usually the last money a lender puts into a job.

Alternatives when construction factoring does not fit

Factoring fits a contractor whose problem is the gap between a verified billing and the owner's check. It fits less well when the problem sits earlier or later in the job.

• A line of credit or mobilization advance funds payroll and the start of a job before there is a billing to sell. Sizing and structure are in contractor lines of credit and mobilization funding.
• Materials financing pays the supplier and is repaid from the draw, at a cost below factoring when materials are the main expense.
• Equipment refinancing raises working capital from a paid-off fleet, covered in construction equipment financing.
• Prompt-payment and lien rights cost nothing. Many states have prompt-payment statutes for construction, and filing lien notices on time shortens owner payment more reliably than any lender.
• Unsecured term loans and revenue-based financing are fast and expensive, and their daily or weekly debits collide with a draw calendar. They fit a short, specific gap and little else.

Mistakes that get construction factoring files declined

• Signing an unconditional lien waiver to get a draw released, then trying to factor the same billing.
• Factoring a billing on a pay-if-paid subcontract without telling the factor, which discovers it at verification.
• Pledging receivables to a bank line and selling them to a factor at the same time.
• Counting the retainage as part of the advance in the contractor's own cash planning.
• Letting the factor's notice of assignment surprise the general contractor instead of explaining it first.

Where MercFinancial fits

MercFinancial is a commercial funding brokerage in Houston, Texas, not a lender, and it does not buy receivables itself. A funding specialist reads the contracts, the pay applications, the aging with retainage separated and the lien position first, then identifies which of the more than 160 funding sources in the network have a credit policy that allows construction receivables and the structure the file supports: a construction factor for the current billings, a retainage lender for a job near close-out, or a line or mobilization advance where the gap sits earlier. One file goes to all of them, the offers are compared on advance rate, fee, verification burden and recourse, and when nothing fits the answer is a plain no. Availability always depends on the funding source. The business funding programs cover the receivable, line and equipment pieces.

Frequently Asked Questions

Can a subcontractor factor progress billings?

Yes, with a construction factor. The factor verifies the pay application with the general contractor, checks the subcontract for pay-if-paid language, takes a conditional lien waiver with the billing, files a notice of assignment and advances most of the billing, with retainage excluded. The balance less the fee is remitted when the general contractor pays. General factors usually decline construction receivables, so the lender has to be a specialist.

Why won't a regular factoring company take construction invoices?

Because a progress billing is not a finished invoice. The amount depends on an inspection, the owner holds back retainage, payment is conditioned on lien waivers, back charges and offsets can reduce it after the fact, and a pay-when-paid clause ties the general contractor's payment to the owner's. Each of those can shrink or delay what the factor collects. Construction factors underwrite all of them and price accordingly.

How much does construction factoring cost?

It depends on the factor, the payer and how long the billing stays unpaid. The advance is commonly within the 70 to 90 percent range factoring runs across industries, often toward the lower end on construction. The fee is quoted per period outstanding, typically per 30 days, on the full billing. A general contractor that pays in 30 days costs far less than one that pays in 75. Terms are set by the funding source.

Can I get an advance on retainage?

Sometimes. Most factors exclude retainage because it has no fixed payment date and is exposed to the punch list and back charges. A smaller set of specialty lenders advances against retainage on jobs at or near completion, underwriting the owner, the close-out status and the contractor's history of collecting retainage. It costs more than factoring a current billing and is usually the last money a lender puts into a job.

Does factoring affect my relationship with the general contractor?

It changes one thing: the general contractor receives a notice of assignment and pays the factor directly. Most general contractors have seen it before, and the verification call is routine. The contractors who run into trouble are the ones who let the notice arrive unannounced or who factor a billing the general contractor has not acknowledged. Explain it first, keep the billings clean, and the relationship is unchanged.

MercFinancial is a commercial funding brokerage in Houston, Texas. MercFinancial is a broker, not a lender: every loan is made by a third-party funding source, every request is subject to that source's underwriting and credit approval, and loan amounts, advance rates, interest rates, terms, fees, collateral and guaranty requirements vary by funding source and borrower and are not guaranteed. Nothing here is a commitment to lend or an offer of credit, and financing is for business purposes only. Any example in this guide is hypothetical and illustrative; actual terms and outcomes vary. Contractors are licensed and bonded under state and local law and lien rights vary by state; financing availability depends on the funding source's policies. This guide is educational only and is not legal, tax, accounting or investment advice.