[Publius Valerius]

Why would one grocery store sell items at a loss during a price war? For only one purpose. To take sales from another grocery store in order to drive them out of business. The prices will go up later if they are successful, bank on it.

This, incidentally, is an antitrust violation.

[Smokin' Joe]

How is a price war an antitrust violation? It happens with 'loss leaders' all the time.

Any large chain which comes into a fresh retail environment can underprice their competition because they have an economy of scale which sometimes permits them to sell items for less than smaller stores can stock them.