Portland, Ore. ? Wal-Mart, the world’s largest retailer, forced employees in Oregon to work unpaid overtime between 1994 and 1999, a federal jury found Thursday in the first of dozens of such lawsuits across the country to come to trial.

A separate trial will be held to decide how much Wal-Mart should pay in damages.

More than 400 employees from 24 of Wal-Mart’s 27 Oregon stores had sued the retailer, accusing it of violating federal and state wage laws.

“I guess, basically, we are disappointed with the verdict. Wal-Mart has a strong policy of paying its associates for all the time they work,” said spokesman Bill Wertz. “We would emphasize that this ruling affects only approximately 350 workers out of 15,000 in Oregon.”

The lawsuit was filed by Carolyn Thiebes and Betty Alderson, who worked in managerial positions at Wal-Mart stores in the Salem area.

The lawsuit claimed managers got employees to work off the clock by asking them to clean up the store after they had clocked out and by deleting hours from time records.

It also said Wal-Mart reprimanded employees who claimed overtime. Workers felt forced to work after clocking out because managers assigned them more work than they could complete in an regular shift, the plaintiffs said.

Wal-Mart conceded during opening arguments Tuesday that some off-the-clock work occurred but said company policy expressly prohibited it.

Wal-Mart, a $218 billion company, employs 1 million workers in 3,250 stores in the United States.

The verdict came after the close of the stock market. Wal-Mart finished the day down 22 cents at $50.16 on the New York Stock Exchange.

Thirty-nine other class-action lawsuits are pending against the company in 30 states.

Those suits, from California to New York, involve hundreds of thousands of workers seeking tens of millions in back pay.