Barclays research predicts that Hurricane Irma's insured damage in Florida could be the largest in U.S. history, a record currently held by that of Hurricane Katrina in 2005.
"Given the potential magnitude of this storm as well as the potential to impact a highly populated area, we think Irma's insured damage in Florida could be the largest ever in the US perhaps equivalent to Hurricane Katrina," wrote Barclays' Jay Gelb on Tuesday.
"In a worst case scenario, catastrophe modelers AIR Worldwide and Karen Clark and Co. have estimated a repeat of the 1926 Miami hurricane could result in $125-130 billion of insured damage."
Hurricane Katrina's insured damage was $50 billion adjusted for inflation.
With winds topping 175 mph, Category 5 Hurricane Irma on Tuesday became the strongest hurricane on record in the Atlantic basin outside of the Caribbean Sea and the Gulf of Mexico, according to the National Hurricane Center. Meteorologists expect the storm to make landfall in the continental U.S. either late this week or early next week.
Even though the storm is not expected to touch Florida for several days, it is already driving home insurance stocks lower.
"We would view Irma as more of a risk to the traditional reinsurers as well as third-party providers of reinsurance capital," noted Gelb. "Of the companies we cover, reinsurers expected to have among the largest exposures to a Florida hurricane could include Everest Group, XL Group, Validus Holdings, RenaissanceRe Holdings, and Aspen."
All the reinsurance companies the analyst noted fell more than 5 percent during Tuesday trade, with Validus down the most at 6.5 percent. XL Group was the single worst performer in the S&P 500, down 6 percent.
Collectively, insurance stocks are having their worst day of 2017. The S&P Insurance Industry (.IUX) is down 1.9 percent, on pace for its worst daily performance since Brexit lows in June 2016, when it fell 3.16 percent. The SPDR S&P Insurance ETF (KIE) is down 3 percent, also on pace for its worst daily performance since June 2016, when it fell 3.14 percent.
The S&P 500 was down more than 1 percent, in part because of the losses by insurers.
"From the insurance industry's perspective, we would expect a substantial hurricane possibly impacting Florida as well as just after Hurricane Harvey to possibly halt further reinsurance price declines for the first time in many years," Gelb said. "However, insurers' earnings and book values would also be expected to suffer a large hit."
— With reporting by Michael Bloom