AQR's founder argues that markets are fundamentally "voting mechanisms" where price is a dollar-weighted average of opinions. Arbitrage is limited because correcting a mispricing becomes progressively riskier for less reward. Therefore, if a misguided belief is backed by enough capital, it can dominate and push prices away from fundamental value.
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With information now ubiquitous, the primary source of market inefficiency is no longer informational but behavioral. The most durable edge is "time arbitrage"—exploiting the market's obsession with short-term results by focusing on a business's normalized potential over a two-to-four-year horizon.
Voltaire believed outcomes are shaped by flawed, human-built institutions, not perfect systems. This philosophy directly challenges the Efficient Market Hypothesis (EMH), which assumes a rational, self-correcting market, suggesting instead that markets are shaped by human and institutional biases.
Contrary to popular belief, the market may be getting less efficient. The dominance of indexing, quant funds, and multi-manager pods—all with short time horizons—creates dislocations. This leaves opportunities for long-term investors to buy valuable assets that are neglected because their path to value creation is uncertain.
AQR's Cliff Asnes argues that markets are becoming less efficient due to social media. It destroys the independence required for the 'wisdom of crowds' to function, creating feedback loops that amplify biases and lead to bouts of irrationality, similar to how it has made politics more extreme.
Following George Soros's theory of reflexivity, markets act like thermostats, not barometers. Rising AI stock prices attract capital, which further drives up prices, creating a self-reinforcing loop. This feedback mechanism detaches asset values from underlying business fundamentals, inflating a bubble based on pure belief.
Unlike physical sciences where observation doesn't change the subject, the stock market's behavior is influenced by participants watching it. A market can rise simply because it has been rising, creating momentum loops. This "self-awareness" means price and value are not independent variables, a key distinction from more rigid scientific models.
The primary driver of market fluctuations is the dramatic shift in attitudes toward risk. In good times, investors become risk-tolerant and chase gains ('Risk is my friend'). In bad times, risk aversion dominates ('Get me out at any price'). This emotional pendulum causes security prices to fluctuate far more than their underlying intrinsic values.
Market-cap-weighted indexes create a perverse momentum loop. As a stock's price rises, its weight in the index increases, forcing new passive capital to buy more of it at inflated prices. This mechanism is the structural opposite of a value-oriented 'buy low, sell high' discipline.
Contrary to classic theory, markets may be growing less efficient. This is driven not only by passive indexing but also by a structural shift in active management towards short-term, quantitative strategies that prioritize immediate price movements over long-term fundamental value.
Quoting G.K. Chesterton, Antti Ilmanen highlights that markets are "nearly reasonable, but not quite." This creates a trap for purely logical investors, as the market's perceived precision is obvious, but its underlying randomness is hidden. This underscores the need for deep humility when forecasting financial markets.
