There are also some symbols that have a dubious relationship to their owners, such as (NYSE: KO) of Coca-Cola Company (were CO or COLA taken?) and (NYSE: LUV) for Southwest Airlines (a bit cutesy).
Among the largest underlying components of DTD, in trading today Wal-Mart Stores, Inc. ( NYSE: WMT) is off about 0.5%, Coca-Cola Co ( NYSE: KO) is up about 0.1%, and Altria Group Inc ( NYSE: MO) is relatively unchanged.