From then on, there would be no change in price of any stock as everyone, through the fund, simply accepted the last going price. There would not even be any reason to have different bid-ask prices. There would be no change in price in a day, a year, or ten years ... no matter what happened to any of the companies whose stock was in the portfolio. Now that would be interesting, we/ the fund could happily be paying big bucks for the stock of shrunken companies, or tiny amounts relatively speaking for vastly expanded others. The investor would receive no capital gains, only dividends, increasing from some successful companies and declining or disappearing from the unsuccessful ones. Things would get very out of whack.
The only change within index funds would come as a result of Standard & Poors or other index providers adding or dropping stocks from indices. It would be rather difficult for the index providers to decide which to include or exclude since the basic method relies on the market capitalization of stocks, a number which would never (or almost never, excepting new stock issuance) change in a totally passive world.
That situation wouldn't be at all stable given the reality that a) stock prices should reflect the value of the profits being generated by the components of the index, b) cagey investors would notice the too-high or too-low craziness of prices and start taking advantage by buying up strong companies with extremely high dividends. Prices would change. Active investors are thus the very mechanism that keeps prices more or less fair. Without the active investors constantly making judgements and moving prices up or down, the passive index investor wouldn't be buying a good product. Nobel Laureate Professor William Sharpe notes this ironic relationship between active and passive investing at the end of his easy-to-read article recommending Index Investing.
Why Stewardship is Proving Elusive for Institutional Investors from the Harvard Law School Forum on Corporate Governance and Financial Regulation notes a further likely effect:
- passive index funds exhibit poor ownership behaviour, effectively letting company management and boards run amok, as the focus on fund cost minimization leaves little money for company oversight and active involvement as a shareholder; in fact, many funds do not even have the shares to be able to vote as they lend them out to generate extra revenue and thus do not have them in hand to vote.
- passive index funds, which own the whole market of perhaps thousands of stocks, cannot practically exercise any corporate owner stewardship even if they attempt it.
Scott Vincent in the April 2011 paper published on SSRN called Is Portfolio Theory Harming Your Portfolio? argues that the rising trend to passive index investing is increasing the opportunities for informed investors to take advantage of market inefficiencies. First, he notes that such informed skilled active investors are not new: " ... In reality, there is an abundance of evidence that markets are less than perfectly efficient, yet most practitioners and academics find that exploiting these inefficiencies is, at minimum, very difficult. It is not easy to consistently outperform the market, but talented managers can and empirical data supports this fact... " He also maintains that most studies of actively managed funds get their measurements wrong because a majority of these supposedly active funds are essentially passive. Instead of holding a few stocks, they are quite diversified in fact and therefore mostly track the index, whether consciously or unconsciously.
Furthermore, he says, "Multiple studies indicate that funds which are more actively managed, or more concentrated, outperform indexes and do so with persistence (Kacperczyk, Sialm and Zheng (2005), Cohen, Polk, Silli (2010), Bakks, Busse, and Greene (2006), Wermers (2003), and Brands, Brown, Gallagher (2003), Cremers and Petajisto (2007))".
According to Vincent, the end result of the contemporary trend to passivity is that: "... as more money flows from truly active managers to investment vehicles that deploy money “blindly,” inefficiencies become more prevalent creating opportunities for those whose eyes are open to them."
Vincent's recommendation is that individual investors can take advantage by a) searching out mis-priced securities themselves, or by b) searching out and investing their money with those truly active and truly successful fund managers - " ... look for concentrated, fundamentally-driven, relatively small funds with talented managers. Since persistence has been demonstrated in this subset, it turns out that a good manager may be identified from past performance".