How Should Contractors Control Vendor and Subcontractor Payments?

Contractors should use payment controls that help ensure every vendor and subcontractor payment is:

legitimate;
properly approved;
accurately coded;
supported by documentation;
and released by an authorized person.

Strong payment processes can help prevent:

duplicate payments;
unauthorized vendors;
fraudulent banking changes;
incorrect project coding;
payments without approval; and
incomplete lien or compliance documentation.

The objective is simple:

Make it difficult for money to leave the company without the right information, approval, and review.

Why Payment Controls Matter in Construction

Construction companies may process payments across:

dozens of projects;
hundreds of vendors;
subcontractors;
field purchases;
purchase orders;
credit cards;
change orders;
and owner or project-manager approvals.

That creates significant transaction volume and many handoffs.

Without a clear process, mistakes can become expensive quickly.

Separate Vendor Setup From Payment Release

One of the strongest controls is separating key responsibilities.

Ideally, the same person should not control every step of:

creating a vendor;
entering an invoice;
approving the invoice;
changing bank information;
releasing payment; and
reconciling the bank account.

The exact structure depends on company size.

But each payment should generally involve more than one point of review.

Control New Vendor Setup

Before a new vendor or subcontractor is activated, management may require:

legal business name;
mailing address;
tax identification information;
W-9;
banking information where applicable;
certificate of insurance;
licensing documentation where relevant;
executed subcontract or purchase agreement; and
internal approval.

The goal is to verify that the vendor is real and authorized before money can be sent.

Restrict Access to Vendor Master Records

Not everyone should be able to create or edit vendors.

Vendor-master access can allow someone to change:

business name;
remittance address;
payment method;
bank account;
routing number; and
tax information.

That access should be limited to appropriate personnel.

Independently Verify Banking Changes

Vendor banking changes are a significant fraud risk.

If an email says:

“Please send all future payments to this new bank account.”

do not rely solely on the email.

A stronger process may require:

contacting a known vendor representative;
using previously established contact information;
verbally confirming the change;
documenting the confirmation; and
having a second person review the update.

The person requesting the change should not control the verification process.

Be Suspicious of Urgent Payment Changes

Warning signs may include:

sudden bank-account changes;
requests for immediate wire transfer;
unusual email addresses;
changes shortly before a large payment;
pressure to bypass normal approvals; and
instructions that differ from prior payment history.

Urgency should increase review—not reduce it.

Use Purchase Orders or Written Commitments

Where practical, significant purchases should be supported by:

purchase order;
subcontract;
approved quote;
or other documented commitment.

That establishes:

approved vendor;
project;
scope;
amount;
cost code;
and authorization.

Accounting can then compare the invoice to what the company actually approved.

Use a Three-Way Review Where Appropriate

For certain purchases, contractors may compare:

Purchase order or contract

evidence goods or services were received

vendor invoice.

This helps prevent:

incorrect quantities;
unauthorized pricing;
duplicate billing;
or payment for goods not received.

Not every transaction requires the same level of formality.

The process should scale with risk and dollar value.

Require Project-Level Approval

A project manager or other responsible person should generally confirm that:

the work was performed;
materials were received;
amount is correct;
project is correct;
cost code is correct;
and payment is appropriate.

Accounting should not be expected to determine project validity from the invoice alone.

Separate Project Approval From Accounting Entry

A useful workflow may look like:

Project Manager

Approves project scope and cost.

Accounting

Enters and validates the invoice.

Controller or Owner

Reviews the payment batch.

Authorized Signer

Releases the funds.

The exact roles may differ, but the sequence should be deliberate.

Control Subcontractor Payments

Subcontractor payments often require additional review because they can involve:

contract amounts;
change orders;
retainage;
lien releases;
insurance;
licensing;
and project-specific compliance.

Before payment, accounting should understand the subcontractor's full financial position on the job.

Track Original Subcontract Amount

For each subcontractor, maintain:

original subcontract amount;
approved change orders;
revised subcontract amount;
billed to date;
retainage;
paid to date;
and remaining commitment.

This helps prevent overpayment.

Separate Approved From Pending Change Orders

A subcontractor may request payment for work related to a pending change.

Management should know whether that change is:

approved;
pending;
disputed;
or rejected.

Do not let project accounting blur those categories.

Confirm Change Orders Before Payment

When a subcontractor invoice exceeds the original contract amount, the payment process should identify why.

Possible explanations include:

approved change order;
allowance;
unit-price adjustment;
correction;
or error.

The excess should not automatically be paid.

Manage Retainage Consistently

Retainage should be calculated and tracked according to:

contract terms;
project requirements;
applicable law; and
company policy.

Accounting should distinguish between:

current payable;
retainage payable;
and amounts not yet due.

Inconsistent retainage processing can distort both project records and cash planning.

Review Lien and Compliance Documentation

Depending on project type and jurisdiction, subcontractor or vendor payments may require documentation such as:

lien releases;
certified payroll;
insurance certificates;
licensing;
tax forms;
safety documentation;
or other compliance records.

The payment workflow should identify which documents are required before release.

Do Not Treat Compliance as an Afterthought

If required documentation is collected only when the project closes, the contractor may lose leverage.

A better process integrates compliance requirements into recurring payment approval.

For example:

No required documentation → payment remains on hold pending resolution.

The specific rule should reflect contractual and legal requirements.

Prevent Duplicate Payments

Duplicate-payment risk can arise when:

invoices are submitted by email and portal;
subcontractors resend invoices;
multiple staff enter the same bill;
invoice numbers are inconsistent;
or manual payments bypass the normal system.

Useful controls may include:

duplicate invoice-number checks;
vendor/amount/date review;
payment batch review;
and system warnings.

Normalize Invoice Entry

If one invoice is entered as:

INV-12345

and another as:

12345

the system may not recognize them as duplicates.

Standardized data-entry practices can improve duplicate detection.

Control Manual and Emergency Payments

Emergency payments often bypass normal procedures.

That creates additional risk.

Contractors should define:

who can request an emergency payment;
who must approve it;
which payment methods may be used;
and how the transaction is documented afterward.

Exceptions should be rare and visible.

Control ACH and Wire Transfers

Electronic payments can move money quickly.

That makes controls especially important.

Useful controls may include:

separate initiation and approval;
dual authorization above defined thresholds;
multi-factor authentication;
restricted bank permissions;
payment limits;
and callback verification for new beneficiaries.

Use Dual Approval for Larger Payments

A contractor may establish approval thresholds such as:

Payments below a defined amount: one approval

Payments above that amount: two approvals

The threshold should be based on company size and risk.

The principle is more important than the exact number.

Review Payment Batches Before Release

Before payments are sent, a reviewer may examine:

vendor name;
amount;
invoice number;
project;
cost code;
approval status;
payment method;
and unusual items.

This final review often catches errors that earlier steps missed.

Review New Vendors in the Payment Batch

A new vendor receiving its first payment may deserve additional attention.

Ask:

Who approved the vendor?
Is documentation complete?
Was bank information verified?
Does the payment relate to a valid project?
Is the amount expected?

First payments are a useful exception category.

Review Unusual Payment Amounts

Large or unusual payments should trigger additional review.

Examples include:

payment materially above normal vendor history;
round-dollar wires;
unusually large advances;
vendor credits not applied;
and payments that exceed contract balance.

Exception reporting can make these easier to identify.

Control Project Coding

Payment controls should protect not only cash but also job-cost information.

Each invoice should be coded to the correct:

project;
cost code;
department;
class;
or other reporting dimension.

Incorrect coding can distort:

job profitability;
WIP;
cost-to-complete estimates;
and financial reporting.

Require Cost-Code Review

Project managers often understand the operational purpose of the cost better than accounting.

The approval workflow can require project managers to confirm both:

invoice validity;
and coding.

That improves downstream reporting.

Reconcile Subledger Information to the General Ledger

Accounts payable, subcontractor commitments, and project costs should reconcile with the accounting system.

Differences can indicate:

missing invoices;
duplicate entries;
coding problems;
or timing issues.

Periodic reconciliation improves confidence in both payables and WIP.

Review Accounts Payable Aging

Management should regularly review:

current payables;
overdue items;
large vendor balances;
disputed invoices;
subcontractor balances;
and retainage.

The aging helps leadership understand upcoming cash needs.

Avoid Managing Cash by Simply Delaying Payments

Stretching every vendor is not a cash-management strategy.

It can create:

damaged supplier relationships;
lost discounts;
reduced credit;
subcontractor disruption;
project delays;
and reputational damage.

Cash flow should be managed through forecasting—not by routinely ignoring payment commitments.

Connect Payment Timing to the Cash Forecast

Large payments should appear in the contractor's cash forecast.

That includes:

major subcontractor draws;
material deposits;
equipment purchases;
tax payments;
and significant vendor obligations.

Track Committed Costs Before Invoices Arrive

A payment may not yet appear in accounts payable even though the company has already committed to it.

Examples include:

signed subcontract;
purchase order;
material order;
equipment deposit;
or committed service agreement.

Those commitments should inform:

project forecasting;
WIP;
and cash planning.

Do Not Rely Only on Accounts Payable

Accounts payable tells management what has already been invoiced.

Committed costs help show what is coming.

That distinction is especially important for construction.

Reconcile Vendor Statements

For significant vendors, periodic statement reconciliation can identify:

missing invoices;
unapplied credits;
duplicate payments;
payment timing issues;
and account discrepancies.

This can be particularly useful for high-volume material suppliers.

Control Credits and Refunds

Vendor credits should be tracked and applied.

Without review, contractors may:

pay invoices in full despite available credits;
lose track of returns;
or leave significant balances unused.

Credits are part of the payment-control process.

Control Advance Payments

Some vendors or subcontractors may require deposits or advances.

These should receive additional scrutiny because the company is paying before receiving full value.

Management should understand:

contractual basis;
amount;
project;
expected delivery;
security or protections available;
and how the advance will be cleared.

Monitor Related-Party Vendors

Transactions with owners, employees, family members, or related entities may warrant additional approval and disclosure.

Controls should make those relationships visible rather than allowing them to blend into routine purchasing.

Separate Payment Method Changes From Invoice Processing

If possible, employees who process invoices should not have unilateral authority to change vendor banking information.

That separation reduces the risk that an altered vendor record could immediately lead to payment.

Restrict Bank Permissions

Bank users should receive only the authority their role requires.

For example:

Accounting Staff

May initiate ACH batches.

Controller

May review.

Owner

May approve large transfers.

Permissions should reflect the approved workflow.

Use Multi-Factor Authentication

Banking, payment, accounting, and email systems should use multi-factor authentication where available.

A compromised email account can otherwise lead to:

fraudulent payment instructions;
fake invoice approvals;
or unauthorized banking changes.

Protect Email Accounts

Many payment fraud schemes begin with compromised email.

Important safeguards may include:

multi-factor authentication;
strong password practices;
phishing awareness;
restricted forwarding rules;
and verification of unusual requests.

Payment control and cybersecurity increasingly overlap.

Review User Access

Periodically review who can:

add vendors;
change vendor banking;
enter invoices;
approve invoices;
release payments;
edit payment limits;
and administer the system.

Former employees and outdated permissions should be removed promptly.

Preserve an Audit Trail

Electronic systems should ideally preserve:

who entered the invoice;
who changed vendor information;
who approved payment;
when approval occurred;
and who released cash.

A clear audit trail helps with both accountability and investigation.

Avoid Approval Through Informal Text Messages

Informal approval may be convenient.

But it can be difficult to:

document;
search;
retain;
and audit.

Where practical, approvals should occur inside a system or workflow that preserves the record.

Use Exception-Based Review

Management does not need to manually inspect every transaction at the same depth.

Exception reporting can highlight:

new vendors;
changed banking information;
duplicate invoice numbers;
large payments;
payments above contract value;
unusual payment methods;
manual checks;
and payments without purchase orders.

That focuses attention where risk is higher.

Establish Payment Thresholds

Approval requirements may increase with payment size.

For example:

Routine payment

Project approval + accounting processing.

Large payment

Project approval + controller approval.

Very large or unusual payment

Project approval + controller + owner approval.

The actual thresholds should be tailored to the company.

Document the Workflow

The payment process should be documented clearly enough that someone new to the organization can understand it.

A simple workflow might be:

Vendor setup → Invoice receipt → Project approval → Accounting review → Payment batch → Management approval → Payment release → Bank reconciliation

Clear processes reduce dependence on tribal knowledge.

Build Payment Controls Into the Monthly Close

Month-end review can identify control issues that occurred during the period.

Leadership may review:

large payments;
new vendors;
vendor changes;
overdue payables;
manual payments;
subcontract balances;
and unusual project costs.

This creates a recurring feedback loop.

Review Payment Controls as the Company Grows

A process that works at:

$5 million of revenue

may not work at:

$30 million.

Growth may require:

stronger segregation;
formal approval thresholds;
electronic AP workflows;
purchase-order systems;
automated vendor verification;
and more formal subcontract controls.

Controls should scale with transaction volume.

A Practical Payment-Control Checklist

Before releasing payment, ask:

Vendor

Is the vendor approved?
Is tax and compliance information complete?
Were banking changes independently verified?

Invoice

Is it valid?
Is it a duplicate?
Does it match the contract, subcontract, or purchase order?

Project

Is the job correct?
Is the cost code correct?
Has the project manager approved it?

Subcontract

Is the contract balance sufficient?
Are change orders approved?
Is retainage correct?
Is required lien or compliance documentation complete?

Payment

Is the amount approved?
Is the payment method appropriate?
Does it require dual authorization?
Is the bank account correct?

Review

Will someone independent review the batch?
Will the transaction be captured in bank reconciliation?

That checklist can prevent a surprising number of problems.

Common Contractor Payment-Control Mistakes

Common mistakes include:

allowing one person to control the full payment cycle;
failing to verify bank changes;
approving payments by informal email or text;
paying subcontractors above contract value;
ignoring retainage;
failing to track pending change orders;
weak project coding;
incomplete lien documentation;
releasing payments before approval;
failing to review new vendors;
and giving too many employees banking permissions.

Most of these risks can be reduced through relatively straightforward process design.

The Bottom Line

Strong vendor and subcontractor payment controls help contractors protect:

cash

project margins

job-cost information

and

vendor relationships.

A strong process should help prevent:

duplicate payments

unauthorized vendors

fraudulent banking changes

incorrect coding

unapproved payments

and

incomplete supporting documentation.

The best control environment creates a clear path from:

commitment → invoice → approval → payment → reconciliation.

That makes payment activity easier to manage, easier to review, and harder to misuse.

How Bilotta & Company Can Help

Bilotta & Company, CPAs, LLC works with construction contractors on internal controls, AP workflows, accounting systems, job costing, WIP reporting, cash-flow forecasting, assurance, tax, and financial leadership.

Through our Contractor Compass® Financial Stewardship program, we help contractors strengthen the processes connecting:

purchasing

vendors

subcontractors

projects

payments

and

financial reporting.

Our Financial Stewardship as a Service® rhythm is:

Close → Analyze → Forecast → Decide.

That rhythm becomes much more reliable when the transactions underneath it are properly authorized, accurately coded, and well controlled.

Explore Contractor Compass® →

Visit the Construction Contractor Financial Resource Center →

This article is provided for general educational purposes and should not be considered accounting, legal, cybersecurity, fraud-prevention, lien, payment, or internal-control advice for a specific contractor. Payment requirements, lien laws, documentation standards, and appropriate controls vary by jurisdiction, contract, company size, systems, and other circumstances.