Revisiting the Numbers on Reversions to Historic Norms

Since October 2023, a combination of Houthi attacks on Red Sea shipping and shippers’ worries about labor unrest closing close East and Gulf Coast ports helped drive container volumes up at America’s West Coast ports.

As Exhibit 4 shows, the U.S. West Coast share of all U.S. inbound container tonnage peaked this past January at 47.0% before falling off in the next two months. Then came April, which saw both President Trump’s Liberation Day announcement of a broad range of sharp tariff increases followed by his decision to pause most of the new tariff rates until July. Since approximately two-thirds of all containerized trade entering U.S. ports originates in East Asia and along the shores of the Indian Ocean, USWC ports again saw a retreat of market share in March and April 2025 to below 40%.

Exhibit 5 illustrates a parallel experience with containerized imports from East Asia. In January, USWC ports handled 67.1% of the value of containerized imports from East Asia and a 57.4% tonnage share. By March, those shares had slipped to 61.9% and 52.1%, respectively. But April’s shares rose again to 62.0% by value and 54.4% by tonnage.