American International Group Inc has led North American insurers to more than $120 billion in debt- market losses, helping to push the tally for the world's biggest financial firms toward the trillion-dollar mark.

AIG, which posted a record third-quarter loss, accounts for about half the insurance industry total through 5 pm on Monday in New York. The losses are three times as costly as Hurricane Katrina, the worst natural disaster in US history.

The falling value of holdings tied to US mortgages contributed to net losses at 15 of the 24 companies in the KBW Insurance Index in the third quarter, and prompted North American insurers to raise more than $80 billion to replenish capital. New York-based AIG helped increase the total of losses among financial companies worldwide to more than $919 billion.