US general insurers are in a strong capital position ahead of the hurricane season beginning next month, according to the Insurance Information Institute.

President Robert Hartwig says the insurers are well capitalised by historical standards, despite sizeable losses in investment portfolios.

The ratio of premiums written to the available surplus stands at 0.95, putting the industry in its strongest position for the past 25 years, surpassing 2001 when the September 11 terrorist attack resulted in insured losses of $US32.5 billion ($43.5 billion) and 2005 when Hurricane Katrina cost $US41 billion ($54.9 billion).