????美國國家經濟研究局（National Bureau of Economic Research）本周發布的最新研究報告《以退為進》（Winning by Losing）由加州大學伯克利分校（the University of California, Berkeley）的教授進行。報告的結論是，雖然收購幾乎總能贏得投資者的掌聲，但最終會對公司（特別是股價）造成負面的影響。報告指出，收購方的股價在收購后三年的漲幅往往比同類公司落后50%。研究還發現，（通常被認為更保守的）現金收購結局往往比換股收購更糟糕。如果被收購公司不愿意接受收購方的股票，投資者自然也不愿意。

????失敗的并購案例不勝枚舉——《財富》雜志（Fortune）母公司時代華納（Time Warner）在互聯網鼎盛時期的一宗收購尤其如此。不過，盡管失敗的并購不在少數，但經濟學家們通常認為并購有益于公司。說到底，如果沒有好處，為什么會出現這么多的并購交易？大多數并購，至少從收購方而言，一般都獲得了良好的市場反響。更重要的是，很難驗證如果不收購，情形會怎樣？你怎么知道如果不進行收購，這家公司會有怎樣的表現？

????為了回答這個問題，加州伯克萊分校（Berkeley）的兩位教授烏爾里克?瑪門迪爾和恩里克?莫萊蒂以及阿姆斯特丹大學（University of Amsterdam）的一位教授佛羅瑞?彼得斯對熱門的競購交易進行了分析，比較了競購成功者與失敗者的股票表現。結果發現，盡管收購前股價走勢相似，但收購后的走勢卻出現了分化，競購成功者的股價表現遠弱于競購失敗者。

????或許人們會說，這是因為競購激烈，收購方不得不提高出價，導致最終的交易不太理想。但三位教授比較了競購交易和無競購交易，結果發現最終的收購估值都差不多。一宗收購有可能因為收購價過高而導致最終結果不理想，但如果是這種情況，它是所有的收購都可能存在的問題，不光是競購交易。

????這對華爾街意味著什么？金融危機期間，投資銀行因為過去的很多行為備受指責。有人質疑，將按揭貸款分割出售究竟給市場經濟增加了什么價值。或許首先要提到的就是按揭債券。但一旦華爾街開始根據打包的按揭貸款抵押資產、出售CDS，要給經濟增加價值？沒門。如果說有什么成果的話，那就是因為華爾街的這些交易，市場經濟以及99%的人們日子都大不如前了。同樣，我們并不清楚投行的并購業務是否給市場經濟帶來了真正的價值。好消息是，沒有證據顯示是投行在拉郎配。往往是首席執行官們自己樂于投身這類前景堪憂的并購。但不管怎樣，華爾街都是同謀，而且從中撈到了大量的油水。

????Beware of Wall Streeters bearing mergers and acquisition advice. That's the takeaway of a new study, and investors should take note as well.

????The study by professors at the University of California, Berkeley, concludes that acquisitions, while nearly always initially cheered by investors, end up hurting a company, and in particular its share price, in the end. Winning by Losing, which was released this week by the National Bureau of Economic Research, found that following an acquisition the stock of that company tends to underperform shares of similar companies by 50% for the next three years. Another finding of the study: Deals done in cash, which is often considered a more conservative way to pay for acquisitions, tend to do worse than deals done for stock. If an acquiring company doesn't want its new owners' shares, you shouldn't either.

????There are tons of examples of deals that have gone south - the one done by Fortune's parent company Time Warner at the height of the dot.com frenzy was a particular doozy. But despite the many bad deals, economists have generally thought mergers are beneficial for companies. Afterall, why would so many of them get done. Most deals, at least from the acquirers' perspective generally get a good reception in the market. What's more, proving otherwise is a hard thing to do. How do you know how a company would have performed without the deal?

????To get around that problem, the two Berkeley professors, Ulrike Malmendier and Enrico Moretti, and a professor from the University of Amsterdam Florian Peters looked at situations where there were hotly contested acquisitions. They then compared the winners of the acquisition bidding war to a similar company that had lost out. What they found is that while the shares of the pairs of companies had tended to perform rather similarly before the acquisition, after the deal the prospects of the two companies diverged, with the company that had made the acquisition performing much more poorly than the company than did not.

????You could argue that in contested bids acquirers tend to be pushed to pay more, and therefore end up with a worse deal than usual. But the professors compared what was paid in the contested deals they looked at and acquisitions where there hadn't been multiple bidders and found that the valuations put on the acquired companies were about the same. So an acquisition may fail because the acquiring company overpays, but if that's the case, that's a problem with all deals, not just when there is a bidding war.

????What does this mean for Wall Street? I-banks have been criticized for many of the things they did during the financial crisis. Some have questioned whether the dicing up of mortgages added any value to the economy. Perhaps on the first go around with mortgage bonds. But once Wall Street got to creating credit default swaps on synthetic tranches of mortgage collaterlized debt obligations, no way. If anything, the economy and the 99% ended up worse off because of all those Wall Street deals. Here, too, it's not clear the I-banks' M&A business is adding any real value to the economy. The good news is that there is no evidence that bankers are pushing companies to do these deals. CEOs are more than happy to launch into ill-fated combinations all on their own. Nonetheless, Wall Street is complicit in the game, and makes plenty of money off it.