Cordiant disclosed details of its breakup into two advertising companies amid news that the London-based holding company hasn't stemmed its revenue decline. Revenue for the first half of 1997 dropped 3.2% despite overall growth in the advertising business. In December, Cordiant plans to split into two groups around its two largest agencies, Saatchi & Saatchi and Bates Worldwide, unraveling an ill-fated merger from the 1980s. Loss of the Miller Brewing account and other business at New York-based Bates Worldwide accounted for most of the revenue decline at Cordiant. Cordiant said that after the split, the value of the outstanding stock of the two agencies would be about the same. Cordiant's American depositary receipts fell 19 cents to close at $6 on the NYSE.