How to Invoice a Large Company
Big companies are great customers and frustrating payers if you ignore their process. Quote the PO, bill the right entity, and reach accounts payable directly to get paid on their terms.
In this answer
- Identify the correct legal entity to bill
- Quote the purchase order their system expects
- Reach accounts payable, not just your project contact
- Meet longer corporate payment terms without losing track
- Keep records ready for procurement and audit
6 min
Bill the right entity, exactly named
Large companies often trade under several legal entities. The invoice must name the exact entity on the purchase order or contract, not the brand you know them by. Billing 'BigBrand' when the paying entity is 'BigBrand Operations Pty Ltd' can stall an invoice in their system.
Confirm the correct legal name, billing address and ABN at engagement. It feels pedantic, but corporate accounts payable systems match on these details, and a mismatch is a common reason invoices bounce. Getting the entity right upfront saves a frustrating round of corrections at payment time.
Quote the PO and match it line for line
Like government, large companies usually issue a purchase order, and their three-way matching process checks the PO against the goods receipt and your invoice. If your line items do not match the PO — different descriptions, quantities or amounts — the invoice can be held automatically.
- Quote the PO number prominently
- Mirror the PO's line structure where you can
- Flag any approved variation against the PO clearly
The closer your invoice maps to the PO, the more likely it sails through without a human having to intervene.
Reach accounts payable directly
Your day-to-day contact at a big company is rarely the person who pays you. Invoices sent only to them can languish in an inbox. Find out where invoices actually go — usually a central accounts payable email or supplier portal — and submit there, copying your contact for visibility.
It is also worth knowing the company's standard payment terms, which can be 30, 45 or even 60 days. Long terms are normal at scale; the trick is to track them so you know when an invoice is genuinely overdue versus simply still within terms, and chase only when it is.
What to include, and following up
Your large-company checklist:
- 'Tax Invoice' (GST if registered) and a unique number, plus your ABN
- The exact paying entity, address and their ABN
- Purchase order number, prominently shown
- Line items mirroring the PO, with approved variations flagged
- Subtotal, GST and total due
- Payment details and their stated terms
- Submission to the AP channel or portal
When an account genuinely runs past terms, a clear statement of account is a professional nudge. Build a clean, PO-friendly layout with the free Invoice Generator.
Key takeaways
- Name the exact paying entity, not just the brand
- Quote the PO and mirror its line structure for clean matching
- Submit to accounts payable, not only your project contact
- Track longer corporate terms so you chase only true overdue
- Use a statement of account as a professional follow-up
Frequently asked questions
Why do big companies take so long to pay?
Large organisations run formal accounts payable processes with set terms, often 30 to 60 days, and matching checks against the PO. It is rarely personal. Submitting correctly and tracking terms is how you keep payment on schedule.
Who should I send the invoice to?
Find the company's accounts payable channel — a central email or supplier portal — and submit there, copying your project contact for visibility. Sending only to your contact is a common cause of delay.
What if my invoice doesn't match the purchase order?
It may be held automatically by their matching system. Align your line items, descriptions and amounts to the PO, and flag any approved variation clearly so it can be reconciled.
Build a compliant invoice in minutes
Use the free Invoice Generator, then let Merion recover anything that goes unpaid — commission-only.