Why business email compromise poses a financial risk for PE-backed companies

Vendor payment fraud results in direct financial loss and a preventable pain point for private equity-backed firms.

In a growing number of cases, attackers are exploiting one of the most ordinary business processes within a company: vendor payments.

Through business email compromise (BEC) and social engineering, bad actors insert themselves into everyday treasury and accounts payable workflows, such as bank account changes, invoice approvals and payment execution. Those workflows operate exactly as designed. The result is not a theoretical cyber event, but real dollars out the door that a business can likely never get back.

From a legal standpoint, these incidents often do not qualify as reportable data breaches. From a business standpoint, they represent immediate and often irreversible value destruction. Treasury and accounts payable (AP) are not back-office administrative functions; they serve as the final control point where cyber risk turns into a balance sheet event.

Why standard payment controls fail

BEC-driven payment fraud succeeds not because organizations lack controls but because those controls were designed for good-faith operations rather than deception. Attackers rarely force their way through systems. They operate within them. Once an email account is compromised, a threat actor gains visibility into:

• Vendor relationships and invoice formats
• Approval chains and sign-offs
• Close cycles, staffing gaps and timing pressure

When the fraudulent request arrives, it often appears legitimate:

• The vendor is real.
• The invoice amount is correct.
• The request mirrors normal communication.

Viewed in isolation, nothing violates policy. At that point, cybersecurity tools are no longer the deciding factor. The outcome hinges entirely on manual treasury and AP controls, including verification steps, segregation of duties, escalation protocols and human judgment under pressure.

Controls designed to prevent errors often fail to detect deception. That is why these incidents continue to occur even in organizations with documented policies, trained staff and no obvious gaps on paper.

Compounding the problem, most companies test these controls in silos. Cyber teams often test access controls. Finance teams test approvals. What is rarely tested is whether a realistic intrusion can successfully trigger a legitimate business process that releases funds.

A real-world example

One middle market, private equity–backed company experienced this pattern firsthand.

A threat actor gained access to an employee’s email account through a routine phishing interaction. No malware was installed. No alerts were triggered. For several weeks, the attacker quietly observed how payments were processed within the company. At the right moment, the attacker intercepted a legitimate vendor invoice and modified just one element: the bank routing information.

The invoice itself was real. The six-figure amount was correct. The vendor relationship was established.

AP processed the invoice using standard procedures. Nothing appeared out of place. Weeks later, the actual vendor called asking why they hadn’t been paid. By then, the funds had already been transferred to the attacker’s account and were unrecoverable.

From a cybersecurity standpoint, the incident was contained. From a financial standpoint, it was a complete control failure.

Why operating partners cannot treat this as an IT problem

For PE operating partners focused on protecting and growing value, BEC-driven payment fraud especially matters for four reasons:

When portfolio companies are most exposed

BEC risk spikes during periods of transition, exactly when PE-backed companies are under the most pressure:

• First 100 days post-acquisition
  New ownership, limited institutional knowledge and process changes create openings.
• Carve-outs and transition service agreement (TSA) transitions
  Legitimate waves of vendor and banking changes provide cover for fraudulent ones.
• Enterprise resource planning (ERP) migrations and system changes
  Temporary control gaps and learning curves normalize exceptions.
• Presale and exit preparation
  Management distraction and urgency increase approval pressure.
• Rapid growth or high turnover
  New AP staff and stretched teams erode consistent verification.

In each case, controls are weakened, assumed or inconsistently applied—exactly the conditions attackers exploit.

The finance-cyber gap that makes this possible

Payment fraud lives in a gap between functions that rarely coordinate in a structured way.

• Finance team own vendor relationships and payments.
• IT and cybersecurity teams own email security and detection.

Neither function owns the full attack surface.

Finance often assumes IT will block bad emails. IT often assumes finance controls will catch anything that gets through. Both assumptions fail at the same time. Lean staffing and speed, features of the PE operating model, only widen this gap if governance and coordination are not deliberate.

Three questions every operating partner should ask

You do not need to be a cyber expert to pressure-test risk. Ask your CFO: