Market concentration of vessel operators#

Market concentration among vessel operators in Pacific Island countries can be analyzed using the Herfindahl-Hirschman Index (HHI): $$HHI=\sum s_i^2$$

Where $s_i$ is the market share of operator $i$. HHI value close to 0 indicates near perfect competition, while HHI value close to 1 indicates monopoly.

Here, the market share is defined by the share of port calls from an operator. We use the port calls data derived from AIS, and the operator information from ship register data. Note that this excludes all vessels not registered with the IMO which is ~12% of port calls from cargo, tanker, and passenger vessels.