Total insurance losses from the Baltimore bridge disaster are expected to exceed $US2.8 billion ($3.9 billion), reflecting a broader range of liabilities than initially anticipated, Howden Re says.

Early market estimates were placed at $US1.5 billion ($2.1 billion) after the container vessel Dali struck the Francis Scott Key Bridge in Baltimore in March 2024.

Howden Re says the figure became the working assumption for much of the marine and reinsurance market through 2024 and into last year, shaping expectations at the January renewals for this year.

MD Hugo Chelton says the scale and speed of the reassessment have caught many off guard.

“The announcement came late on a Friday,” he said. “By Monday morning it had gained real momentum. A $US1.3 billion ($1.8 billion) deterioration would be a major loss event in its own right – let alone when layered on top of what was already one of the largest marine losses.”

Most of the loss will be absorbed by the reinsurance and retrocession markets.

“As the loss grows, it becomes increasingly concentrated,” Mr Chelton said. “The deepest exposure lies with the large reinsurers and the retro market. For some participants, relative to their own capital base, this will represent a very significant single loss.”

At the higher level, the bridge collapse would rank as the largest single marine insurance loss on record, surpassing about $US1.6 billion from the Costa Concordia cruise ship grounding in 2012.