US-based companies reporting financial damage from hurricanes Harvey, Irma or Maria had collectively lost $US18 billion ($26.3 billion) in market value by August the following year, a study shows.

The FM Global commissioned analysis, undertaken by Pentland Analytics, looked at filings to the US Securities and Exchange Commission and modelled the stock prices of 52 companies.

The findings show hurricane-related impacts caused a 5% hit to shareholder value over the period following the catastrophes.

FM Global says a separate dataset related to the hurricanes also highlights companies that followed all the insurer’s engineering advice relating to storm protection collectively outperformed clients that hadn’t by 10%.

“The lessons are clear,” Pentland Analytics founding director Deborah Pretty said. “First hurricanes damage shareholder value as well as property values. Second, property protection pays off.”

Harvey, Irma and Maria hit the US coastline in August and September 2017. The National Oceanic and Atmospheric Administration estimates the combined costs of the hurricanes at $US265 billion ($387.4 billion).