Holo-chrome and Danaher make tools for most, Stanley, Craftsman, etc. American Yard Products makes most of the chain saws and lawnmowers for Poulan, Sears, Roper, Troy Built, Husqvarna, MTD, etc. Vermont American makes most of the drillbit and saw blades.
However these are only the manufacturers. The marketing department for each labeled company determines the pricing and quality that goes into each brand.