Wal-Mart Stores will leave most of its 833 U.S. discount stores open overnight on Thanksgiving to avoid crowds gathering to get specials the following morning after an employee was trampled to death a year ago.

Most of those stores will remain open after their regular closing hour of 11 p.m., allowing customers to remain inside to wait for the ``Black Friday'' special prices that start at 5 a.m., David Tovar, a company spokesman, said Tuesday in a telephone interview. Wal-Mart developed plans for each of its stores to manage the flow of customers as they get in, seek discounted merchandise, check out and leave on ``Black Friday.'' The store in Valley Stream, N.Y., where Jdimytai Damour, a temporary worker, was trampled on Nov. 28, 2008, is among those staying open overnight, Tovar said.

``We would anticipate not having these long lines outside the stores,'' Tovar said from Bentonville, Ark., where Walmart is based.

The company's 2,705 supercenters, which sell general merchandise and groceries, already operate 24 hours a day.

The holiday shopping season traditionally starts on so-called `Black Friday,' the day after Thanksgiving. `Black Friday' is Nov. 27 this year. Jockeying for discounted merchandise may intensify this year as rising unemployment makes consumers more desperate for bargains and retailers deepen markdowns to spur sales, National Retail Federation executives said Tuesday on a conference call.

The NRF recommended merchants coordinate crowd control with local police and assign employees to interact with shoppers, as well as spread discounted items, which Wal-Mart plans to do.