May saw a sharp increase in inbound boxes assisted by frontloading in the month that typically starts the peak season. Importers want to get loads in earlier due to increasing uncertainty regarding future tariffs. In May, inbound boxes at the 10 largest U.S. ports were up 15.8% compared to last May. That is the largest percent increase in 21 months and is a sharp swing sequentially from April, which had the largest percent decrease in 32 months. The May increase comes after April’s 8.3% decrease and March’s 1.1% increase. The three-month trailing figures came in at a 2.3% increase in May, a sharp expansion on April’s 4.3% three-month trailing decrease.
That trailing figure snapped 11 straight months before that were negative that followed 19 months that came before that were all positive readings. That metric has still generally been in a downward trend since the beginning of 2025. The trailing six-month total figure in May was down 1.7%, compared to being down 5.0% in April. The trailing 12-month figure for April was down 2.9%, an improvement from the 4.6% decline in April and the 3.2% decline in March. The May measure broke what had been a consistent downtrend for 14 straight months through April for the 12-month figure.
Inbound analysis
May’s overall inbound volume of 2,136,493 TEU’s was the largest in the last nine months. Compared sequentially to April, it was 11.0% higher. That was a sharp and extraordinary contrast with the 12.1% sequential decrease last year. That 23.1% variance underscores my earlier observation and estimates of some noteworthy frontloading in May.
Actual May inbound volume was 21.6% above 2019, which translates into a 2.8% CAGR and above recent actual CAGR’s excluding the March anomaly of 4.4%. For instance, the average actual CAGR for earlier months in 2025 excluding March was 2.1%. If one assumes that is the underlying growth rate absent any frontloading, the proforma May inbound volume would have been 15.7% above 2019. That would have translated into a proforma year over year increase in May of 10.1% or some two-thirds of the actual 15.8% growth. That indicates to me that the actual change in May has around one-third of the increase due to frontloading. If it is frontloading, that is more of a timing difference and should become apparent as we get further into the year. However, with the various cross currents related to changing tariffs and different perceptions among shippers as to which direction they are going in, this year will likely continue to show lots of erratic movements.
U.S. inbound volume this May compared to May 2019 was 21.6% higher, which is equivalent to a seven-year CAGR of 2.8%. That growth rate measure was above the 2.1% in April but below the 4.4% in March.
Outbound analysis
Outbound or export boxes over-performed import boxes from mid-2022 to late 2023, but since then have shown erratic up and down moves that circle in to a slight uptrend over the last year. Total outbound volume was up 3.7% in May. The latest month was an improvement compared to the 0.5% increase in April and the 0.3% increase in March. Twenty-six of the last 46 months have shown increases following fourteen straight months of decreases. The trailing twelve-month figure in May for total outbound volume showed an increase of 1.3% compared to an increase of 0.8% in April and 0.6% in March.
With May outbound volume up 3.7% and inbound volume up 15.8%, there was a 1210-basis point directional gap in favor of inbound volume. That is a reversal of April where there was an 880-basis point directional gap in favor of outbound and well above the 80-basis point inbound advantage in March. The May inbound advantage was the largest in 16 months since a 1830-basis point advantage in January 2025. May was more than twice the average 560 basis point gap by which inbound growth has exceeded outbound growth over the last 70 months.
With exports, only 28 of the last 75 months have shown year over year gains, with a 1.2% average monthly decline over the period. While total inbound loads this May were 21.6% above what they were seven years ago during May 2019 for a 2.8% CAGR, total outbound loads were 9.9% less resulting in a negative 1.5% CAGR. That 430-basis point difference in directional growth rates over a seven-year period is a noteworthy divergence in the overall performance of exports compared to imports over the same period. The May metric was above the 350-basis point difference in April but below the 560-basis point difference in March.
U.S. vs the rest of the world
The gap between volume trends in North America and the rest of the world continues, although there has been some amelioration the past couple of months. This can be seen in the graph below based on trailing three-month year over year changes during 2025 through April, the last month of available worldwide data. Based on that trailing three-month metric, North America went from a 2.8 percentage point overperformer at the beginning of 2025 to a 5.8 percentage point underperformer in April, a striking swing of 8.6 percentage points. That three-month metric is down from a 14.6 percentage point peak in January.
When U.S. container volume data is compared to global data and data in major global regions, there has been a noticeable gap for a year now as the downtrends in U.S. lanes are being significantly mitigated by increased volume in other regions.
In April, worldwide container volume showed a year over year gain of 4.3%, a noticeable rebound from the 1.9% decline in March. Contributors to the March weakness include the Iran situation, which shutdown container volume related to the Persian Gulf, as well as the varying dates of the Chinese New Year. The April gain of 4.3% was below the average gain of 4.9% over the preceding 12 months. The largest change related to import volume was the 18.7% decrease in Mideast/India imports with the Persian Gulf still closed off. All other regions showed import volume gains above the global average led by Australia (up 9.7%), Africa (up 8.4%) and Far East (up 7.1%). The largest change on the export side was the 14.5% decline in Mideast/India. The other noteworthy changes in export volume were Far East (up 8.9%) and North America (down 3.2%), while the other regions showed modest changes that were primarily negative.
As the data shows, world container supply chains have already begun to adapt and reconfigure trading patterns faster than most thought while U.S. volume languishes and declines. The volume gains those regions have represent more growth and less inflation than the U.S. should have had.
These container volume reports not only telegraph future economic activity driven by the law of large numbers, but they will be a particularly useful tool going forward. In a period that is expected to have a number of macro catalysts, actual volume trends provide data to assess the impact of tariffs on both economic activity and growth as well as inflation.
To put into better context the commercial activity that is impacted from changes in container volume, it is useful to know that the average value of goods moving in containers is pegged from studies at $54,493 per TEU. Using that figure, the total value of goods in containers moving in and out of all U.S. ports including the two dozen container ports outside of the Top 10 ports in May was $190.9 billion. That is the equivalent of $2.291 trillion in annualized economic activity.
Whether it involves increases or decreases, material changes in what is a meaningful portion of the U.S. economy will have pronounced positive and negative effects across the economy. For example, a 10% reduction in overall container volume from this point on based on tariffs is in my view possible. Such a decrease would translate directly into a $229 billion reduction in annual commerce for the U.S.
Shifting port activity
The West Coast ports have outperformed the East/Gulf Coast ports in 23 of the last 34 months. Those 11 months that were the exceptions were a return to the period that saw a streak of 26 straight months where the East/Gulf Coast ports out-performed West Coast ports.
May showed a 20.8 percentage point coastal gap favoring West Coast ports based on an 27.4% increase at West Coast ports compared to the 6.6% increase at East/Gulf Coast ports. The May gap was a pronounced widening of the West Coast advantage, which was 8.7 percentage points in April in contrast with a 7.4 percentage point March advantage for East/Gulf Coast ports.
The trailing three-month figures give a clearer picture of trends and the recent westward shift abatement over the previous eight months has tempered. In May that measure showed the West Coast ports with an advantage of 6.0 percentage points compared to 2.3 percentage points in April and an East/Gulf Coast port advantage of 5.9 percentage points in March. Despite two straight months of reversing the previous eight months, the May measure was still well below the 25.8 percentage point record West Coast advantage for the three months ending November 2023. Only 11 of the last 34 periods had East/Gulf Coast ports outperforming on this metric. The West Coast advantages go back to September 2023 and East/Gulf Coast ports had the advantage during the prior 29 months as can be seen on the chart below.
Even with some rebound in volume to the West Coast, the underlying shift eastward and away from the West Coast since 2016 is evident. Over the seven-year period, the trend points to an average shift of some 50 basis points per year. If the data were looked at over a longer period going back to before the canal expansion, the shift would be more in the range of 75 basis points per year. These periods benefited from the expanded Panama Canal and the more than three times larger container ships it allowed so the shift going forward will not be as high. However, my analysis is that there will continue to be an eastward shift in the range of 35 basis points per year. This will be driven primarily by the superior cost economics of moving containers by water compared to land as well as relative U.S. population distribution and growth.
Traffic by port
Ports with the strongest May performance were Long Beach (up 40.0%), Los Angeles (up 26.2%) and Houston (up 13.4%). The ports with the weakest performance were Charleston (down 4.9%), New York (up 4.4%) and Oakland (up 5.7%). . Stronger performers over the last three months were Los Angeles (up 9.3%), Long Beach (up 7.6%) and Houston (up 3.9%). Weaker performers were Seattle/Tacoma (down 12.1%), Charleston (down 7.0%) and Savannah (down 4.0%). Over the last twelve months, the stronger performers were Houston (up 1.5%), Los Angeles (down 0.2%) and New York (down 1.2%). The weaker performers were Seattle/Tacoma (down 20.2%), Charleston (down 6.5%) and Long Beach (down 4.0%).
Container pricing
The CTS global pricing index, the definitive measure of overall sector pricing, has come out for April and was at 89, a 12.6% increase from the 79 level in March. Note that this and other indices include the impact of fuel surcharges, which ratcheted up sharply in April. The April index was 14.5% above the average 77.7 level in 1Q26 and 17.6% above the average 75.7 level in 4Q25. From its recent monthly peak level of 118 in July 2024, the CTS global pricing index has generally been declining since then.
The latest readings on the SCFI index, the most closely followed spot index measure, augment overall pricing insight into the container sector. Pricing in most container lanes involving the U.S. shows trends similar to those in broader measures as the lanes are invariably linked in what is really a single pricing matrix. While there are credibility issues with the various spot pricing indices based on how they are determined and who provides input, they do provide information on the direction and trend of pricing. The SCFI began trending down last December and has generally been in a downtrend. However, in the last few months it has spiked up as pricing has tightened related to the hostilities in the Middle East. All pricing indices include the impact of fuel which has sharply increased since the beginning of those hostilities. The latest SCFI reading of 3122 on June 19 is 108.3% above the 1Q26 average of 1499 and 44.6% above the May average of 2159.
This is an excerpt of the McCown Container Volume Observer, which features an exhaustive deep dive into the facts and figures behind U.S. container shipping volumes, including analysis of monthly trends by port and by direction. The observations and data in the 25-page report include some 20 graphs and tables, providing timely container volume and pricing information. To subscribe to The McCown Report, visit The McCown Report site.
About the author: John D. McCown is an internationally recognized shipping expert with over four decades of experience in the sector. He currently serves as a Non-Resident Senior Fellow at the Center for Maritime Strategy, the think tank of the Navy League. McCown was the co-founder and former CEO of U.S. flag container carrier Trailer Bridge, Inc. He also focused on the shipping and transportation industries from an investment perspective as the transport sector head at a $20 billion hedge fund.
