When you do not have to pay.

Since May 28, 2024, demurrage and detention invoices on US ocean trades have had to follow the Federal Maritime Commission's billing rules in 46 CFR Part 541. The rules apply to invoices from ocean carriers, NVOCCs and marine terminal operators. They govern how a charge is billed, not how much the daily rate can be.

Rule 1: the invoice must be complete

Every invoice must carry a minimum set of information, including the bill of lading and container numbers, the free time and its dates, the dates charged, and the rule the rate comes from. If any required information is missing, the billed party has no obligation to pay that charge (46 CFR 541.5 and 541.6).

Rule 2: the invoice must be on time

A billing party must issue the invoice within 30 calendar days of the date the charge was last incurred. If it does not, the billed party is not required to pay the charge. An NVOCC passing on a charge it was billed has 30 calendar days from the date of the invoice it received (46 CFR 541.7).

Rule 3: you get time to dispute

The billing party must give you at least 30 calendar days from the invoice date to request mitigation, refund or waiver. Once you send a request, it must try to resolve it within 30 calendar days, or a later date both sides agree to (46 CFR 541.8).

What changed in 2025

On September 23, 2025, a federal appeals court set aside one section of these rules, 46 CFR 541.4, which had limited who could be billed. The FMC removed that section from the rules. Everything else in Part 541 remains in effect.

What the rules do not do

The rules do not cancel fair charges. The FMC has been clear that if an invoice complies with the rules, the billed party is obligated to pay it. The point is not to avoid every charge. It is to pay only what was billed correctly.

A quick test for any invoice

• Is every required item on the invoice?
• Was it issued within 30 days of the last day charged?
• Are you still inside the window to request mitigation, refund or waiver?

If the answer to the first or second question is no, that line may not be owed at all. If both are yes, the next step is checking the dates and the rate. How to check a demurrage invoice, line by line

If you would like a second set of eyes, Zenmul reviews freight charges and gives you a written report. You decide what to submit to the carrier, and you submit it yourself.

This article is a plain summary of published rules, not legal advice.