Executive Summary
Demurrage and detention (D&D) remain among the least predictable lines on an ocean freight budget. FMC data show that nine major carriers collected roughly $15.4 billion in D&D charges between April 2020 and March 2025, though billings and collections declined in the first quarter of 2025. Since May 28, 2024, the FMC’s billing rule (46 CFR Part 541) has required D&D invoices to contain specific information and to be issued within 30 calendar days of the last incurred charge; the FMC states that failure to meet either requirement eliminates the billed party’s obligation to pay the charge. Billed parties have at least 30 days to request mitigation, refund, or waiver. Separately, charge complaints under the Ocean Shipping Reform Act of 2022 put the burden of showing that a charge is reasonable on the carrier, and a final rule effective September 1, 2026 clarified the two available complaint paths. This guide explains the two clocks, the invoice rules, the dispute and complaint options, and practical ways to reduce exposure.

Demurrage and Detention: A Practical Guide to FMC Invoice Rules, Disputes, and Avoidance

(滞港费与滞箱费实用指南：FMC发票规则、争议处理与避免之道)

1 · The Scale of the Issue

What the FMC Data Show

The FMC collects quarterly D&D data from nine ocean carriers: CMA CGM, COSCO, Evergreen, Hapag-Lloyd, HMM, Maersk, MSC, ONE, and Yang Ming.

Source: Federal Maritime Commission, Detention and Demurrage Data (the most recent summary available to us covers through March 2025).

These figures reflect charges billed by and paid to the nine carriers by their customers—shippers, consignees, truckers, and others—not only importers. The FMC data are best read as a measure of scale rather than a count of improper charges.

The Two Clocks

Demurrage and detention are separate charges with different triggers:

How One Can Lead to the Other

Moving a container out of the terminal promptly stops demurrage but starts the detention clock. On any lane, slow unloading or difficulty returning the empty can lead to detention charges following demurrage, so the two need to be monitored together.

⚠️ Key Point: Demurrage and detention are two separate clocks that can run in sequence. Gating out ends one and begins the other.

2 · The FMC Invoice Rules

The Basics

Required by the Ocean Shipping Reform Act of 2022, the FMC’s billing rule is codified at 46 CFR Part 541 and took effect on May 28, 2024. It applies to invoices issued by ocean carriers, marine terminal operators, and NVOCCs for demurrage or detention. Two points do much of the work:

• Invoice content. An invoice must contain specific minimum information.
• Timing. The billing party must issue the invoice within 30 calendar days of the last date on which the charge was incurred (an NVOCC has 30 days from receiving the underlying invoice).

The FMC states that failure to comply with either requirement eliminates any obligation of the billed party to pay the applicable charge, and that billing parties risk being found in violation of the Shipping Act.

The Required Information

The rule’s list is detailed; in summary, an invoice must include:

• Identifying information: bill of lading number(s), container number(s), and, for imports, the port(s) of discharge
• The basis for why the billed party is the proper party to be billed
• Timing information: invoice date and due date; the specific date(s) for which charges are billed; the free time allowed, with its start and end dates; for imports, the container availability date; for exports, the earliest return date
• Rate information: the total amount due, the applicable rule on which the rate is based, and the specific rate(s) under the tariff or service contract
• Dispute contact information
• Required certification statements

The text of 46 CFR 541.6 controls; consult it when reviewing a specific invoice.

The Dispute Window

The billing party must give the billed party at least 30 calendar days from the invoice date to request mitigation, refund, or waiver of charges, and must attempt to resolve a request within 30 calendar days of receiving it. Practitioners note that this dispute window operates alongside, and separately from, the invoice-content and timing rules, so it is prudent to put a written dispute on record within the window rather than rely on a defect alone.

The 2025 Court Decision

In 2025, the D.C. Circuit decided World Shipping Council v. FMC and set aside only 46 CFR 541.4, the provision that limited whom a carrier could invoice, finding the FMC’s rationale inadequately explained. The practical result is that carriers may invoice motor carriers with whom they have a contractual relationship. The FMC has emphasized that, apart from section 541.4, the rest of the rule remains in effect, including the invoice-content and 30-day issuance requirements.

⚠️ Key Point: An invoice that omits required information or arrives late is, under the FMC’s reading, one the billed party has no obligation to pay. Because carriers may take a different view of a specific invoice, many companies document the defect, dispute in writing within 30 days, and involve counsel where significant sums are at stake.

3 · The Charge Complaint Process

What a Charge Complaint Is

Under OSRA 2022, any person may submit information to the FMC about charges assessed by a common carrier. The FMC is directed to investigate and, where charges do not comply with the shipping laws, may order refunds and penalties. In a charge complaint, the carrier bears the burden of showing that its demurrage or detention charges are reasonable.

Two Paths

As we discussed in our earlier analysis of the FMC’s final rule effective September 1, 2026, a charge complaint can be pursued two ways:

The rule also bars filing a duplicate claim for charges that have already been decided on the merits.

What Counts as Unreasonable

The FMC evaluates reasonableness case by case, guided by its 2020 interpretive rule, which treats detention and demurrage as incentives for efficient equipment use. Under that rule, and absent extenuating circumstances, detention charges imposed when an empty container cannot be returned are likely to be found unreasonable.

Two decisions illustrate the approach:

• In TCW v. Evergreen, the FMC found that charging detention while a port was closed and equipment could not be returned was unreasonable, and awarded reparations; on remand it affirmed that result but withdrew a blanket cease-and-desist order, emphasizing that each case must be evaluated on its facts. The D.C. Circuit unanimously upheld the FMC’s conclusion in April 2026. Notably, the FMC indicated that advance notice of a closure does not by itself make the charges reasonable.
• In an earlier matter, the FMC found detention charges unreasonable where appointments to return empty containers were unavailable.

⚠️ Key Point: Charges are most open to challenge where the billed party could not realistically pick up or return the container—for example, because the terminal was closed or appointments were unavailable. Documentation of those circumstances is what supports the claim.

4 · A Practical Dispute Approach

Step 1: Check the Invoice Against the Rule

Compare the invoice to the required information in 46 CFR 541.6. Note any missing fields, such as the container availability date, free time dates, or the rate basis.

Step 2: Check the Timing

Confirm whether the invoice was issued within 30 calendar days of the last incurred charge.

Step 3: Review the Facts Behind the Charge

Even a compliant invoice may involve charges that can be questioned:

Step 4: Put a Written Request on Record

Submit a request for mitigation, refund, or waiver within the 30-day window. The billing party has 30 days to attempt to resolve it.

Step 5: Consider a Charge Complaint

If the matter is not resolved, the interim procedure offers a no-fee option with FMC staff assistance; a traditional complaint is available where a formal decision is wanted.

Step 6: Document Everything

For each disputed charge, keep the invoice, gate schedules and closure notices, availability notifications, appointment logs, communications with the carrier, and any evidence of congestion, weather, or terminal problems.

5 · Practical Approaches to Reducing Exposure

1. Pre-clear customs before arrival. Submitting documentation before the vessel arrives helps containers move as soon as they are discharged.
2. Track the last free day for each container. Prioritize pickups by last free day rather than by vessel arrival estimates.
3. Review free time in service contracts. Terms that can be negotiated include extended free time, flexibility in peak periods, and waiver triggers during congestion.
4. Pre-book drayage and chassis. Appointments and booked equipment reduce terminal wait times.
5. Consider transloading near the gateway. Shortening the distance to the unloading point can speed the return of empty equipment.
6. Use visibility tools. Real-time information on container status, terminal conditions, and free time expiry helps flag risks early.
7. Keep port and terminal alternatives in mind. As our coverage of port congestion notes, delays concentrate at particular gateways.
8. Confirm what starts the free time clock. Carriers may count from container availability, gate-in, discharge, or other triggers; the difference can be days.
9. Separate equipment charges from terminal storage. Carrier free time does not necessarily waive terminal storage or other terminal charges, which may be billed separately.

6 · Considerations for Logistics Providers

Forwarders, brokers, and 3PLs often sit between carriers and customers when D&D arises. Considerations include:

• Invoice review as a standard step, with a checklist built from 46 CFR 541.6 and the 30-day issuance deadline
• Clear contract language on who is the billed party and how D&D invoices are handled, since the court’s 2025 decision allows carriers to invoice parties with contractual privity
• Dispute deadlines tracked from the invoice date, so that a written request is made within the 30-day window
• Evidence retention: gate-in/gate-out times, appointment logs, and notices of closure or congestion
• Customer reporting on free time, last free day, and D&D exposure by container
• Awareness of the complaint options, including the no-fee interim procedure, for charges that cannot be resolved directly

7 · Conclusion: Managing a Controllable Cost

Key Takeaways

The Takeaway

Demurrage and detention can be managed, and in some cases disputed. The FMC’s rules give billed parties specific protections—a content requirement, a 30-day issuance deadline, a dispute window, and a complaint process in which the carrier carries the burden—but they work best with timely review and good records. Companies that check invoices against the rule, track free time, and keep evidence of delays outside their control are in the strongest position to manage this cost.

If your organization would like help reviewing D&D invoices or building a process for tracking free time and disputes, our team is available.

This analysis reflects FMC regulations at 46 CFR Part 541 and the FMC’s published guidance, the FMC’s detention and demurrage data through March 2025, the D.C. Circuit’s decisions in World Shipping Council v. FMC and in the TCW v. Evergreen matter as reported by the FMC and trade press, and the FMC’s charge complaint final rule effective September 1, 2026. Invoice requirements, deadlines, and complaint procedures depend on the facts of each case. Importers and logistics providers should consult trade counsel and maritime professionals for guidance tailored to their specific circumstances.