Sears, Roebuck and Co., the nation's biggest retailer, kicked off its largest ever holiday advertising and promotion campaign on Thanksgiving, a step that could set off a price war among the big chains.

Despite lean inventories and improved pricing vs. last year, a price war could squeeze profits at Sears' competitors, if the Chicago-based merchant succeeds in carving out a bigger market share for itself.But analysts expressed skepticism, given Sears' history, that the pricing would be competitive enough to worry rivals.

"There's going to be a lot of advertising over the weekend when a lot of people will see it. The question is will it be effective and will it draw people into the stores," said retail analyst Terry McEvoy of Swergold, Chefitz and Sinsabaugh Inc.