股票市场的估价与并购

苏州大学商学院

摘要：近年来，很少有关于兼并和收购的商业话题博得许多研究和媒体的关注。在过去40年来，经济理论提供了许多根据-关于为什么公司选择从事企业兼并与收购，看法不一。 实证研究表明，这些理论最能解释某些类型的并购活动，虽然有些理论似乎是更加适用于某些特定时间段。合并后的公司似乎稍微好一点了。最近的许多研究对将M＆A公司设法将个体公司的市场估值以及整体股票指数跟合并行为以及表现联系起来。

关键词：估值合并并购表现股票市场

Abstract:In recent years,few business topics have commanded as much research and media attention as mergers and acquisitions. Over the past 40 years,economic theory has provided many rationales-positive and negative-for why firms choose to engage in mergers and acquisitions.Empirical research has shown that most of these theories can explain certain types of merger activity, though some theories appear to be more relevant for particular time periods.The combined entity seems to be slightly better off. Much of the recent research in M&A has sought to link the market valuations of individual companies,as well as overall stock market levels, with merger activity and performance.

Key words: valuationmergeracquisitionsperformancestock market

Introduction:

In recent years,few business topics have commanded as much research and media attention as mergers and acquisitions,perhaps because of the sheer volume of M&A activity: the value of U.S.merger activity equaled around 16% of GDP in 1999 and the value of M&A worldwide reached a peak of $3.5 trillion in 2000.

Over the past 40 years,economic theory has provided many rationales ―positive and negative ― for why firms choose to engage in mergers and acquisitions.For example,acquirers may be seeking to improve efficiency or create market power,or be reacting to deregulation;in other cases,diversification or empire building may be the goal ― possibly spurred by managerial hubris.Indeed,empirical research has shown that most of these theories can explain certain types of merger activity,though some theories appear to be more relevant for particular time periods.Much of the academic and anecdotal research has focused on this crucial question: Do mergers and acquisitions create value？ Interestingly,the answer is not clear.Whether acquisitions create value depends on various factors: how value improvements are measured;the participant examined;the type of deal;the method of payment;the type of target;and the bidder's,the target's or the market's valuation.

Measures of Value Creation

There are three popular ways to measure whether mergers create value.The first measure ― the short-run stock performance of the acquirer,the target or the combined entity surrounding the acquisition announcement ― is the most widely used in studies.Many view short-run stock performance as the most reliable evidence of value creation because in an efficient capital market,stock prices quickly adjust to new information and incorporate any changes in value that the acquisitions are expected to bring.Rather than considering actual stock returns occurring over a few days,these studies focus on abnormal returns.That is,they deduct the return investors could have earned by investing in the market as a whole.

The second measure of value creation is the long-run stock performance of the acquiring firm for three to five years after the acquisition announcement.Studies show that certain acquirers significantly underperform their peers in the long run,thereby casting doubt on the conventional wisdom that stock prices adjust quickly and fully during the announcement period.Long-run studies also focus on abnormal performance,not relative to the market,but relative to nonacquiring peers of the acquiring firm.Abnormal performance is measured as the stock return of the acquirer minus the stock return of a nonmerging firm of similar size and marketto- book ratio as the acquirer.

The third way to measure value creation is to examine accounting measures of profitability―including return on equity or assets―and cash-flow performance.If acquisitions create value for shareholders,these gains should improve a firm's performance and profitability.Similar to the long-run stock performance measure,these studies address whether acquirers outperformed their peers,where peers are defined as nonacquiring firms in the same industry with similar size and profitability as the acquirer.

The Valuation-Performance Link

Much of the recent research in M&A has sought to link the market valuations of individual companies,as well as overall stock market levels,with merger activity and performance.

The idea that stock prices affect merger activity is not new.It dates back at least to Ralph Nelson,who noted that merger activity seems to boom when stock prices are high.Boyan Jovanovic and Peter Rousseau confirmed this observation,showing that periods of high merger activity correlate with high market valuations.Further,during these merger waves,firms are more likely to use stock to undertake acquisitions.Recently,however,researchers have begun to explore whether market valuations affect the performance of mergers.Numerous studies have shown that acquirers who pay with stock underperform their peers in the long run,whereas acquirers who pay cash outperform their peers.Kenneth Martin's work suggested such a link when he showed that acquirers using stock tend to have high market to-book ratios and acquirers using cash have had low market-to-book ratios;numerous studies have shown that acquirers who pay with stock underperform,whereas acquirers who pay cash outperform.This suggested link between firm valuation and merger performance was established more directly by Raghavendra Rau and Theo Vermaelen.They compare the performance of “glamour firms” with that of “value stocks”.Because the glamour firms have typically performed well in the past,the authors hypothesize that the stock market overextrapolates positive past performance when assessing acquisitions and management overestimates its own abilities.

Therefore,merger activity is often valuedestroying and such glamour firms indeed underperform their peers in the long run.

Reference:

Bouwman,C.H.S.,K.Fuller and A.S.Nain,“The Performance of Stock-Price Driven Acquisitions,” working paper,University of Michigan and University of Georgia （2003）.

Dong,M.,D.Hirshleifer,S.Richardson and S.H.Teoh,“Does Investor Misvaluation Drive the Takeover Market？” working paper,York University,Ohio State University and University of Pennsylvania （2003）.

Holmstrom,Kaplan,“Corporate Governance and Merger Activity in the United States: Making Sense of the 1980s and 1990s,” Journal of Economic Perspectives 15,no.2 （2001）

Jovanovic,B.,and P.Rousseau,“Mergers and Technological Change: 1885-2001,” working paper,New York University （2001）.