BENTONVILLE, Ark. (AP) — Wal-Mart is spending $1 billion to make changes to how it pays and trains U.S. hourly workers.

As part of its biggest investment in worker training and pay ever, Wal-Mart tells The Associated Press that within the next six months it will give raises to about 500,000 workers. That’s nearly 40 percent of its 1.3 million U.S. employees.

Wal-Mart follows other retailers that have boosted hourly pay recently, but because it’s the nation’s largest private employer, the impact of its move will be more closely watched.

In addition to raises, Wal-Mart said it plans to make changes to how workers are scheduled and add training programs for sales staff so that employees can more easily map out their future at the company.

Also today, Wal-Mart reported a 12 percent increase in profit for the fourth quarter as sale for the critical holiday shopping season perked up amid lower gas prices and an improving economy.

But the company said its plays to improve pay and training will hurt profits in the short run.

The world’s largest retailer has struggled for two years with sluggish sales.