指數基金的優點眾所周知。它們的投資回報率往往高于主動管理型共同基金，部分原因是費率較低。這讓指數基金成為美國最受歡迎的投資方式之一。美國投資公司協會的數據顯示，2015年1-11月流入指數基金的資金規模接近1450億美元。同時，主動型共同基金流失資金1610億美元。但對我們這些受益者來說，好處太多反而可能有害。

近期，多項研究都得出了一個類似的結論。這些研究發現，指數基金規模的增長正在逐步瓦解真正的股東精神。出現這個問題的原因在于，指數基金是所謂的被動型投資者，也就是說，這些基金及其經理人不挑選投資對象。這項工作由創立相關指數的公司完成，比如標準普爾。指數基金投資者只能隨波逐流。

這樣的做法一直有助于提高投資回報率。許多研究都表明，投資者買賣股票的時機往往有誤，就連職業投資者也不例外。晨星最新的主動/被動投資晴雨表報告顯示，主動型基金的表現全面落后于被動型基金。在截至2014年底的10年時間里，逾四分之三的美國主動型大盤股基金的表現都不如同樣權重的被動型基金群體。

這對散戶來說可能是件好事，但它不利于整體經濟或整個市場。新的研究指出，隨著被動型投資者的持股比例越來越高，他們開始改變公司的管理方式。首先，公司將提案提交股東大會審議時，占比不斷增長的被動型股東也會行使權利。盡管不采用主動管理方式，但指數基金持有的股份仍有投票權。賓夕法尼亞州立大學學者彼得?伊利耶夫和米歇爾?勞里撰寫的論文指出，問題在于這些基金更有可能作為一個團體進行投票，而傳統的主動型基金“‘整齊劃一’地進行投票的可能性較小”。因此，指數基金越多，就意味著在管理層之上的不同群體越少。

其次，沃頓商學院教授伊安?阿佩爾、托德?戈姆利和唐納德?凱姆在名為《被動型投資者，而非被動型所有者》（Passive Investors, Not Passive Owners）的論文中指出，雖然指數基金不會盯著各位經營者，但它們較有可能投票支持將權力從管理層手中收回的提案。論文指出：“看來被動型投資者的影響力來自于他們巨大的投票群體。被動型股東的特點是不怎么支持管理層的提議，但較為支持股東就治理問題提出的建議。”

對存在問題的公司來說，這是件好事。但對于實際上擁有優秀管理層的公司來說，這會削弱管理者的權力。由于被動型基金沒能力挑選投資目標，它們對待所有公司的方法似乎都一樣。

最后，在同一行業中，指數基金往往不僅持有一家公司的股票，它們的持股范圍還會覆蓋這家公司的大多數競爭對手。密歇根大學金融學助理教授馬丁?施邁茨和咨詢公司Charles River Associates高級合伙人何塞?阿扎爾以及伊莎貝爾?特庫共同撰文指出，由此造成的局面是持股過于集中，而且像貝萊德或Vanguard這樣的大型指數基金公司可以用被動型基金持有的股票來投票。這會在相關行業引發反競爭行為。

比如說，美國飛機票價上升11%的原因是追蹤標普500指數的那些龍頭指數基金不光持有美國航空的股票，還持有達美航空和聯合航空的股份。這樣的全面持股模式造成這些公司不太可能愿意跟對手展開競爭。如果這聽起來還有些玄乎，那就用施邁茨的方法，把這些航空公司比作街對角的兩座加油站。如果所有者不同，它們也許就會相互壓價。然而，“如果這兩座加油站都歸你所有，你還會讓它們這樣做嗎？很可能不會。”

施邁茨擔心，缺乏競爭會推動消費品價格上升，從而削弱經濟活力。此外，其他研究還表明，指數基金的結構對股市來說也是個問題。

資產管理公司Osterweis Capital Management創始人兼首席投資官約翰?奧斯特維斯指出，其中的原因在于指數基金采用市值權重法。這種方法往往有利于那些規模最大的公司，而這些公司在最受歡迎的指數中占的比重也最大，這就會產生“強者愈強”效應。同時，隨著這些公司的市場價值不斷增長，它們在指數基金投資中占的比例也持續上升。奧斯特維斯以今年上半年的回報率為例。他說，在標普500指數中，最大的10只個股平均上漲了35%，而其余490只股票的平均跌幅幾乎達到7%。

奧斯特維斯認為，由此產生的結果是，指數基金把自己的投資者困在了幾家公司里，而其他投資者也在購買這些公司的股票，這往往會造成后者股價過高。他說：“你買的股票可能會在一段時間里表現不佳，但最終你的投資收益也許會超過別人，原因就是你可能沒有跳進這些陷阱里。”問題在于，指數基金的力量是否也讓經濟進入了這些陷阱之中。（財富中文網）

譯者：Charlie

校對：詹妮

The virtue of index funds is well known. They tend to offer higher investment returns than actively managed mutual funds, in part because of their lower fees. That’s made them one of the most popular investments in America. Nearly $145 billion flowed into these funds in the first 11 months of the year, according to Investment Company Institute. At the same time, $161 billion flowed out of actively managed mutual funds. But perhaps we have gotten too much of a good thing.

That’s the conclusion of a number of recent research studies that came out this year. Their findings: The growth in the amount of money in index funds is chipping away at the true spirit of stock ownership. The issue has to do with the fact that index funds are so-called passive investors, meaning the funds and their managers don’t pick the companies they invest in. They are selected by an the company that creates the index, like Standard & Poor’s. And the investors have to go along for the ride.

That’s been good for investment returns. Many studies have proven, that investors, even professionals, tend to buy and sell at the wrong time. According to Morningstar’s most recent Active/Passive Barometer report, actively managed funds have generally underperformed their passive counterparts. More than three-quarters of active managers in the U.S. Large Cap category lagged the equal-weighted composite of their passive peers during the ten years ending December 31, 2014.

But what may be good for investors individually, may not be good for the economy or the market as a whole. As passive owners snag a larger and larger share of the companies in the market, they change how companies are managed, so the new studies say. First of all, their growing presence during proxy season wields power, when companies put up proposals to shareholder votes. And although they aren’t actively run, index funds still vote shares. The problem is index funds are more likely to vote as a group, according to a paper from Peter Iliev and Michelle Lowry at Penn State University. Traditional actively managed funds are “less likely to vote in a ‘one size fits all’ manner,” according to the paper. So more index funds means fewer disparate groups are keeping on top of management.

Second, while they aren’t watching individual managers, index funds are more likely to vote for provisions that take power away from managements, according to a papers from Wharton School professors Ian Appel, Todd Gormley, and Donald Keim, titled “Passive Investors, Not Passive Owners.”“Passive investors appear to exert influence through their large voting blocs—passive ownership is associated with less support for management proposals and more support for shareholder-initiated governance proposals,” the paper says.

That’s good for problem companies, but it can dilute the power of companies that actually have too good leaders. And passive funds, which don’t have the ability to chose, seem to treat all companies the same way.

Lastly, index funds tend to not just own one company in an industry, but most of their rivals as well. What happens, according to a paper Martin Schmalz, assistant professor of finance at University of Michigan wrote with Jose Azar and Isabel Tecu of Charles River Associates, is that stock ownership becomes too concentrated when companies like Blackrock or Vanguard, two large managers of index funds, vote the shares of passive funds. It can create anti-competitive behavior in an industry.

For example, U.S. airline tickets prices are 11% higher because the largest index funds that track the S&P 500 own not just American Airlines, but Deltaand United Continentalas well. And common ownership makes companies less likely to want to compete with rivals. If that sounds like hocus pocus, Schmalz likens it to two gasoline companies on opposing corners. If they have different owners, they might undercut each other’s prices. However, “if you own both gas stations on both sides of the street, are you still going to do the same thing? Probably not.”

Schmalz worries that a lack of competition is driving up prices for consumers and making the economy less dynamic. But other research suggests that the structure of index funds is a trouble for the stock market as well.

The reason John Osterweis, founder and chief investment officer of Osterweis Capital Management, says is because index funds are capitalization weighted. This dynamic often favors the largest companies, which make up the largest weights in the most popular index, and it has a momentum effect. And as those companies’ market value gets bigger, a greater percentage of the money index funds invest flow to those companies. Osterweis points to the returns in the first part of this year as an example. In the S&P 500, the top 10 contributors were up an average of 35%, while the bottom 490 stocks in the index were down almost 7%, he says.

The result, Osterweis says, is that investors through index funds get trapped in a few companies, and it’s the same companies everyone else is buying, so they tend to be over priced. “You might underperform for a period of time, but ultimately you might outperform because you might not be trapped in this thing,” says Osterweis. The question is whether index funds have become such a force that they have the economy trapped as well.