NVOCC stands for non-vessel operating common carrier. That means that it doesn’t operate actual vessels, yet they are considered to be common carriers for the purposes of U.S. law. There are similar categories of carriers in the European Union and elsewhere.
NVOCCs are essentially consolidators, both of less-than-containerload freight and of smaller volumes of containers. They negotiate favorable shipping rates with vessel operating carriers based on the volume they are able to consign, and pass those advantages along to their customers. Smaller shippers that can’t get a good rate, or any rate, from a vessel carrier, consign their loads to the NVOCC under the intermediary’s contract with the carrier.
In the past, NVOCCs were were not allowed to enter into confidential service contracts with shippers as were their vessel-operating counterparts. Instead, all freight had to move pursuant to publicly filed tarrifs. That has since changed, but the NVOCCs still do not enjoy the partial immunity from antitrust law as do the vessel operators.