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VESSEL SCHEDULE STABILITY INDEX · MONTHLY

VSSI Monthly - March 2026

Port-level stability measurement, with timestamped snapshots retained for dispute defense. The measurement layer underneath the TVI quarterly index.

5Ports measured
1,041Vessel departures
9,393CRW changes
MEASUREMENT LAYER - published monthly

What VSSI Measures

The Vessel Schedule Stability Index (VSSI) rolls up vessel-level CRW movement into a single port-level score, with timestamped snapshots retained for dispute defense. It is the measurement layer of the TradeLanes publication ladder: it proves that the patterns surfaced weekly in DTB and the structural shifts diagnosed monthly in The Loaded Box hold up at the port-aggregate level.

Higher VSSI scores indicate more stable schedules. Lower scores flag ports where vessel schedules are actively moving in the weeks before departure.

This month, one port's VSSI fell 20 points against its prior-month reading. The same port's DTB Weekly flags had been elevated for three consecutive weeks before the monthly number confirmed it.

Port Stability Ratings

Sortable by any column. Lower VSSI score = less stable. Tier assignments follow the standard deviation bands of the cross-port mean.

Port UNLOCODE VSSI Score Tier Vessels CRW Changes
Los Angeles USLAX 56 Elevated 142 1847
New York/NJ USEWR 48 Elevated 189 2103
Oakland USOAK 77 Moderate 211 1340
Houston USHOU 79 Moderate 198 892
Savannah USSAV 35 Unstable 301 3211

Sample Vessels This Month

Highest-shift vessels contributing to this month's port readings. Full vessel log available in the weekly DTB.

Vessel Carrier Service Port ERD Shift CY Cut Shift Stability Late-Stage
MAERSK NEWARK MAEU TP6 Savannah +3.2d +2.1d High Late Stage
ONE WREN ONEY FP1 Oakland −0.8d 0.0d Elevated Late Stage
CMA CGM THALASSA CMDU GGB Houston 0.0d 0.0d Stable No
COSCO SHIPPING ARIES COSU AAC3 Los Angeles +1.5d +1.2d Moderate No
MSC ANNA MSCU NJX New York/NJ −1.1d −0.6d Elevated No

Methodology Note

VSSI rolls up vessel-level CRW distributions into a port-level score. For each vessel departing in the measurement month, we compute the cumulative absolute shift in ERD and CY Cut against the originally published window. Vessel-level values are aggregated with the standard VSSI-P formula (see full methodology), stratified by operating environment, and tiered against the cross-port baseline.

Ports need a minimum sample of 40 vessel departures to qualify for tier assignment. Below that, the reading is shown but marked provisional.

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Previous Editions

March 2026 February 2026 January 2026 December 2025

Explore Related Intelligence

VSSI is the measurement layer. The full publication ladder:

QUARTERLY · INDEX

Terminal Volatility Index

Terminal-level structural measurement. Quarterly cadence.

 WEEKLY · DETECTION

DTB Weekly

Vessel-level signal layer. What moved this week.

 MONTHLY · DIAGNOSIS

The Loaded Box

Editorial analysis of structural patterns and operator implications.

Rob Prather
Bill Hewitt,
Frey Commodities
"TradeLanes gives us control over the entire load order process, in real time. I highly recommended signing up to try their new early access product."