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on共同基金業(yè)績的一致性,一直都是一個燙手的話題 – Carhart – weak evidence of persistency較弱的證據(jù),而且成本大過收益 – Bollen and Busse – support for performance persistence over short time horizons較短的期限內(nèi)有一致性 – Berk and Green – skilled managers will attract new funds until the costs of managing those extra funds drive alphas down to 金經(jīng)理會吸引更多資金直至費用越來越高最后投資的阿爾法收益消失 Mutual Fund Performance 共同基金的表現(xiàn) INVESTMENTS | BODIE, KANE, MARCUS 1132 Figure Riskadjusted performance in ranking quarter and following quarter 根據(jù)季度和下季度風(fēng)險調(diào)整后的排名:兩個季度的對比 可以看出微弱的一致性:強(qiáng)的還會強(qiáng),弱的也還是弱,但是差距變小很多幾乎不可見了。 if it could be predicted, then the prediction would be part of today’s information.新的信息是不可預(yù)測的,如果是可預(yù)測的信息馬上就會帶來股價變動從而成為了今天的信息 ? Stock prices that change in response to new (unpredictable) information also must move ,第二天的股票價格變動一定反應(yīng)了今天所無法預(yù)知的信息,因為今天每一點每一滴能夠預(yù)知和使用的信息都會反映在今天的價格變動中 ? Stock price changes follow a random 辦法預(yù)測的未來運動模式成為隨機(jī)漫步 INVESTMENTS | BODIE, KANE, MARCUS 115 Figure Cumulative Abnormal Returns Before Takeover Attempts: Target Companies目標(biāo)公司接管前累計的異常收益:只是宣布消息的那天會有異常變動 INVESTMENTS | BODIE, KANE, MARCUS 116 Figure Stock Price Reaction to CNBC Reports市場價格對 CNBC報道的反應(yīng) INVESTMENTS | BODIE, KANE, MARCUS 117 ? Information: The most precious modity on Wall Street 信息是華爾街最寶貴的商品 – Strong petition assures prices reflect 效信息 – Informationgathering is motivated by desire for higher investment 資收益所驅(qū)動的 – The marginal return on research activity may be so small that only managers of the largest portfolios will find them worth 收益太低,只有大規(guī)模的基金管理人才會有動機(jī)去做研究分析等 EMH and Competition 有效市場假說與競爭 INVESTMENTS | BODIE, KANE, MARCUS 118 ? Weak弱式假說認(rèn)為市場的股票歷史價格、成交量等市場公開信息已經(jīng)無用,都已反映在目前的股票價格里; ? Semistrong半強(qiáng)式假說任何公司財務(wù)信息、預(yù)期、以及一切公開可得的信息都已無用,反映在當(dāng)前股票價格里; ? Strong強(qiáng)式假說認(rèn)為任何信息都已反映在股票價格信息里,包括內(nèi)幕消息 Versions of the EMH 有效市場假說的不同版本 INVESTMENTS | BODIE, KANE, MARCUS 119 ? Technical Analysis using prices and volume information to predict future prices技術(shù)分析是利用股票價格、成交量等信息預(yù)測未來價格走勢 – Success depends on a sluggish response of stock prices to