Invoice fraud in construction: why subcontractor payments are a target

Construction sees more invoice and mandate fraud, relative to its size, than almost any other UK sector. It’s not because construction finance teams are less careful — it’s because the structure of the industry creates more opportunities for fraud to slip through.

Why construction is a target

A typical project involves a long chain of subcontractors, each invoicing separately, often onboarded quickly to keep a project moving. New supplier relationships, frequent one-off payments, and the sheer number of invoices in flight at any given time all work against manual checking. Property and construction consistently rank among the sectors most targeted by fraud aimed at SMEs, and the pattern is straightforward: more suppliers and more invoices means more chances for one fake to look exactly like the genuine 50 around it.

The specific patterns worth watching for

Three patterns show up disproportionately often in construction invoice fraud:

• Fake-subcontractor invoices — fraudsters create a plausible-looking subcontractor, sometimes using a real trading name with slightly altered details, and invoice for work that was never done or was already paid for.
• Mandate fraud on existing subcontractors — a genuine subcontractor’s email is compromised or spoofed, and a “bank details have changed” message arrives that looks completely routine.
• Circular billing between connected suppliers — a pattern where several seemingly unrelated suppliers are actually connected, designed to make fraudulent invoicing harder to spot by spreading it across multiple supplier names.

What actually helps

The controls that work best in construction aren’t exotic — they’re the same fundamentals applied consistently despite the volume: verifying bank detail changes by phone for every subcontractor, regardless of how long they’ve worked with you; checking new suppliers against your existing supplier list for similar names or details; and mapping which suppliers are connected to each other, so a circular billing pattern is visible rather than buried across separate-looking invoices.

That last one — seeing how suppliers connect to each other — is genuinely difficult to do by hand once you’re past a handful of subcontractors, which is exactly the kind of check we built into Invixa’s supplier-network analysis for construction clients specifically.