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 2,765. Case's share of that market was 22 percent, while Fiat comprised just 12 percent of the market. If approved, by how much would the post-merger Herfindahl-Hirschman index increase? Based only on this information, do you think the Justice Department would challenge the merger? Explain.