  Maritime shipping is a backbone of international trade and, thus, the world
economy. Cargo-loaded vessels travel from one country's port to another via an
underlying port-to-port transport network, contributing to international trade
values of countries en route. We hypothesize that ports that involve
trans-shipment activities serve as a third-party broker to mediate trade
between two foreign countries and contribute to the corresponding country's
status in international trade. We test this hypothesis using a port-level
dataset of global liner shipping services. We propose two indices that quantify
the importance of countries in the global liner shipping network and show that
they explain a large amount of variation in individual countries' international
trade values and related measures. These results support a long-standing view
in maritime economics, which has yet to be directly tested, that countries that
are strongly integrated into the global maritime transportation network have
enhanced access to global markets and trade opportunities.
