A bizarre Mexican Supreme court judgment that has turned an international limitation of liability convention on its head is causing big waves in insurance and shipping markets.

The Mexican courts have ruled that owners of an offshore supply vessel that hit a rig cannot benefit from the widely adopted 1976 Convention on Limitation of Liability for Maritime Claims (LLMC).

The convention limits the liability of ships but not drilling rigs or production platforms in more than 50 countries covering over half the world’s tonnage.