Dynamic merger policy and pre-merger product choice by an entrant
研究了并购可能性如何影响潜在进入者的产品选择，发现仅关注并购后福利的政策可能扭曲进入者的投资方向，有时批准福利为负的并购反而更优。
We examine the effects of merger and merger policy on a potential entrant's pre-merger product choice. We establish conditions under which the possibility of merger can induce an entrant to imitate an incumbent's product instead of innovating with a more differentiated product. Turning to policy, current practice is to evaluate a proposed merger by focusing on post-merger effects (e.g., whether the merged firm will charge higher prices or invest less in innovation than would the two firms if they remained independent of one another). We show that policies focused solely on a proposed merger's ex post welfare effects can induce an entrant to choose an inefficient direction for its pre-merger investment decisions. We also show that, taking into account merger policy's effects on pre-merger product choice, it can be optimal to approve mergers with a positive probability even when the post-merger welfare effects of every consummated merger are negative.