DALLAS (AP) _ A jury ordered Mexican billionaire Carlos Slim Helu and four co-defendants to pay $360 million in damages to a Dallas company Thursday, saying they derailed the company's plans to open CompUSA stores in Mexico.

The company, COC Services Ltd., said its exclusive agreement to open the stores hinged on finding an investor.

Slim expressed interest in helping them finance the deal. But, COC's owners testified that Slim and his associates halted talks after gaining insider information about CompUSA, which Slim bought a few months later for $800 million.

COC sued Slim, CompUSA, former CompUSA Chief Executive Jim Halpin and two companies controlled by Slim as defendants.

The state jury awarded $90 million in actual damages for lost profits and $270 million in punitive damages.

``The message sent by the verdict is that in this global economy, companies need to abide by United States rules if they come here,'' said Mark Werbner, attorney for COC. ``You are not allowed to interfere with contractual rights of others.''

A spokesman in Mexico City for Slim, whose family-run financial empire includes control over Telmex, the Mexican phone company, said he had no comment on the verdict.

The defendants said COC never had a final deal to operate CompUSA stores in Mexico, only unsigned letters of intent to negotiate if COC ever found a partner.

Slim, one of his sons and a son-in-law all testified that the COC proposal didn't make business sense. Slim testified it was a ``risky business'' because of intense competition from Wal-Mart and other retailers and because of the lack of a large, affluent middle class that could afford computers.

Last year, Forbes magazine ranked Slim the wealthiest man in Latin America, pegging his personal fortune at $7.9 billion.