Suppose Fiat recently entered into an Agreement and Plan of Merger with Case for $4.3 billion. Prior to the merger, the market for four-wheel-drive tractors consisted of five firms. The market was highly concentrated, with a Herfindahl-Hirschman index of 2,650. Case's share of that market was 18 percent, while Fiat comprised just 9 percent of the market. If approved, by how much would the postmerger Herfindahl-Hirschman index increase? Based only on this information, is the Justice Department likely to challenge the merger according to the Horizontal Merger Guidelines? O Yes O Possibly - but other factors will be considered O No