About 12,000 workers, or 7 percent of Starbucks' global workforce, will be affected by the closings, which are expected between late July and the middle of 2009, spokeswoman Valerie O'Neil said.

Seventy percent of the stores scheduled for closure had opened after the start of 2006, Starbucks said in a statement.

To put it another way, Starbucks is closing 19 percent of all U.S. company-operated stores that opened in the last two years, chief financial officer Pete Bocian said during a conference call.

O'Neil said most employees would be moved to nearby stores, but she did not know exactly how many jobs would be lost. Starbucks estimated $8 million in severance costs.

In total, the company forecast up to $348 million in charges related to the closures, $200 million to be booked in the fiscal third quarter ended June 30. Starbucks reports third-quarter results at the end of July.

The 500 additional stores set to be closed had been on an internal watch list for some time. They were not profitable and not expected to be profitable in the foreseeable future, and the "vast majority" had been opened near another company-operated Starbucks, Bocian said.

Some analysts had wondered whether Starbucks' explosive U.S. growth would come back to haunt it as the market became saturated.

But before yesterday, the company avoided acknowledging that saturation was an issue, and blamed the economy for weak financial results and adjustments to new store openings.

During the call, Bocian said that between 25 percent and 30 percent of a Starbucks shop's revenue was cannibalized when a new store opened nearby and that the closures should help return some of that revenue to the remaining stores.

Bocian said that there were not a material number of stores left on the watch list, but that the company would hold remaining stores to the same standards.

Starbucks still plans to open new stores in fiscal 2009, but yesterday, it cut that number in half, to fewer than 200. The company did not adjust its plan to open fewer than 400 stores in 2010 and 2011.

At the end of March, there were 16,226 Starbucks stores around the world. The company operates 7,257 of those stores in the United States and 1,867 abroad; the remaining 7,102 locations are run by partners who license the Starbucks brand.