Not surprisingly, the destruction of lives, homes, and buildings from last month’s historic earthquake and tsunami outside Tokyo has hit the earnings figures of insurance companies and, more significantly, reinsurance companies.

Buyers of commercial insurance in the United States will likely not see significantly higher rates any time soon, however. “We don’t think insurers and reinsurers are going to sustain enough of a financial loss to trigger them or force them to reconsider how much capacity they’re willing to offer, and in turn it will not move rates as much as expected,” says Francois Morin, global product leader, property-and-casualty claims reserving, for consultancy Towers Watson.

Much of the financial loss — estimated to be above $300 billion — from the magnitude 9.0 earthquake was either not insured or will be covered by the Japanese government. For that reason, Towers Watson estimates that insured losses from the disaster will total only between $20 billion and $45 billion. (The firm also notes that liabilities that will arise from the country’s nuclear reactors are also not “significantly” insured by the private sector.) Moreover, the ripple effects won’t be as steep for U.S. insurers as they were five years ago following Hurricane Katrina.

Japan’s catastrophe was a “medium-size event” for commercial-property insurer FM Global, says CFO Jeffrey Burchill, but will be a large event for the reinsurance industry. Indeed, the March 11 earthquake “is going to damage profitability [of insurance companies], but it’s not digging into capital just yet,” says David Bradford, editor-in-chief at Advisen, a risk-data analysis firm.

In a report released last week, Advisen predicts that although other factors may move rates upward as early as 2012, the rise will be slow. As it is, the average premiums for commercial lines — including property and workers’ compensation insurance — have been moderately declining since 2003, according to Advisen’s index aggregating renewal data from risk managers and insurance brokers (see chart). Advisen says the industry could see a price shift as demand increases under an improved economy, putting a dent in what has lately been an overcapitalized market. Rates could also take a turn, of course, if the United States were to experience a catastrophic event of its own.

Some insurance companies will likely see higher rates when they renew their reinsurance this summer to protect themselves against losses during the hurricane season, warns Morin. While it’s too early to accurately predict the increases, industry observers believe regions close to the coasts could see 10% to 30% rate increases in reinsurance, he adds. Higher estimates incorporated into a widely used hurricane model, now known as RMS version 11.0, will likely contribute to this rise in prices. It could take another six months, says Morin, for those costs to trickle down to the companies that need property-and-casualty insurance.

Editor’s Note: This article has been updated to include a corrected figure for estimated economic losses and insured losses in Japan.