The short answer
Level 3 is the richest of the three commercial card data levels. When you pass line-item detail (SKU, quantity, unit price, tax, freight, customer code, commodity code) alongside a B2B card charge, Visa and Mastercard give you interchange rates 0.30–1.00% cheaper than the default commercial tier.
In plain English
Commercial and government-issued cards (purchasing cards, corporate cards, fleet cards) get special interchange treatment — if you prove the transaction is really B2B by sending B2B-grade data. Level 1 is just the amount. Level 2 adds tax and customer code. Level 3 adds a line-item array plus freight, duty, ship-from and ship-to postal codes, and commodity codes.
The fields (Visa/MC Level 3)
- Header — customer reference code, purchase order number, total tax amount, tax rate, ship-from ZIP, ship-to ZIP, destination country, freight amount, duty amount, order date.
- Line item (repeats per SKU) — item commodity code, product code / SKU, item description, quantity, unit of measure, unit cost, line item tax amount, line item tax rate, discount per line, net total per line.
Miss any header field and the whole transaction downgrades. Miss a line item field and that line item downgrades.
What operators need to know
- Only helps B2B / GSA cards — consumer debit and credit don't care about Level 3. If your volume is 90% consumer, skip it.
- Must match invoice — totals across line items must equal the auth amount to the cent, or the transaction downgrades.
- Stripe supports it via `level3` param on the PaymentIntent. Most WooCommerce setups don't send it by default.
- Square does not support Level 3 on most plans. If your B2B AR runs on Square, you're leaving 40–80 bps per transaction on the table.
- Auth + capture timing — Level 3 data must be on the capture call, not just the auth.
Why multi-brand operators care
If any of your brands sell wholesale or to businesses, Level 3 changes the unit economics of that channel. A brand doing $500K/yr of B2B on a commercial card that isn't sending Level 3 is overpaying ~$3K/yr. Across a five-brand portfolio, that's real money for maybe a day of integration work.