Billing Corporate Customers: TINs, Billing Contacts and Approvals

Selling to a company is good business: bigger orders, repeat work, customers who rarely disappear. Billing them is a different skill from billing individuals. Their accounts payable team processes hundreds of supplier invoices, and anything that doesn't match their records goes back to the supplier. Each rejection restarts the clock, often by weeks. Most of those rejections are avoidable with one good set-up.

Why corporate invoices bounce

From the customer's side, an invoice is checked against three things: their supplier record, their purchase order, and their tax obligations. Typical reasons for sending one back:

• The legal name doesn't match the supplier record ("Bakare Advisory" vs "Bakare Advisory Services Limited").
• The customer's TIN is missing or wrong, so they can't account for VAT or WHT properly.
• There's no PO number, or the wrong one.
• The amount doesn't match the PO, or VAT is shown where they didn't expect it (or missing where they did).
• It went to the wrong person: the manager who ordered the work, not the accounts mailbox.
• It's addressed to the parent company, but the purchase was made by a subsidiary.

None of these is about whether they'll pay. All of them decide when.

Set up the customer properly, once

Before the first invoice, collect these details and store them on the customer record, not in an email thread.

The Nigeria Tax Administration Act 2025 makes a TIN mandatory for taxable persons (Mondaq), and commentary on VAT invoice requirements lists the supplier's TIN and business registration number among the details an invoice should carry (Invoice Data Extraction). Guidance on exactly which buyer details NRS e-invoicing requires is still settling, so put the customer's TIN on every invoice anyway: corporate customers need it for their own VAT and WHT records. Confirm the current required fields with your adviser.

Learn their approval process

Your invoice joins their approval workflow. Ask three questions at the start of the relationship:

1. Do you need a purchase order number on every invoice? If yes, don't start work without one.
2. Who approves supplier invoices, and what's your payment run? Many companies pay on fixed days. Knowing that "the run is every second Thursday" tells you when to invoice.
3. Will you deduct withholding tax, and at what rate? For consultancy and professional services, for example, a 5% deduction from the fee is common practice under the Deduction of Tax at Source (Withholding) Regulations 2024 (EY). Knowing in advance stops you chasing a "short payment" that's really tax. Our WHT guide covers rates and credit notes.

A worked example

Bakare Advisory Services Ltd, a consultancy in Ikeja, finishes a review for Lekki Heights Montessori Ltd under PO 4500-2231.

The last two lines are for Bakare Advisory's own records, not the invoice. Because they were agreed upfront, Chiamaka Obi in accounts knows that ₦1,025,000 landing in the bank means "paid, awaiting WHT credit note", not "₦50,000 short".

Groups and subsidiaries

When you sell to a group, bill the entity that placed the order. If the parent company buys on behalf of a subsidiary, agree in writing which entity receives the invoice and whose TIN goes on it. Record the parent on each customer so you can see total exposure to the group, but keep invoices and statements per legal entity. That's how their accounts are kept, and matching it removes a whole class of queries.

A first-invoice checklist for a new company customer

• Legal name, TIN and RC number confirmed against their documents
• Correct entity in the group identified
• Billing contact and CCs recorded
• PO received, and its number and amount match the invoice
• VAT treatment agreed; WHT expectation noted
• Their payment run date known
• Invoice reviewed by a second person before sending
• A clear way to pay on the invoice

How Flux helps

Flux stores company customers with their legal name, TIN, VAT number, RC number, parent company, number of entities and external reference, plus primary and CC billing contacts, so every invoice carries the right details automatically. Invoices go through your approval workflow before they're emailed, and statements show the account at a glance. See Invoicing & Billing.