The shift to index funds was triggered not by a belief in market efficiency, but by the surprising discovery that alternative investments are highly tax-inefficient for individuals due to non-deductible fees and ordinary income, creating a tax drag of up to 20%.
Advisors who recommend fixed allocations like 60/40 without considering current expected returns and risk are committing a form of 'malpractice.' Investment decisions must be dynamic, as the relationship between risk and return is not constant over time.
In an experiment where participants could trade on Monday's prices after seeing Wednesday's newspaper, the average person could not make money. This demonstrates the profound difficulty of translating perfect macro information into profitable trades, as market reactions are unpredictable.
Investors extrapolating future returns from recent performance is a more damaging force in markets than underestimating fat tails or the rise of passive indexing. This behavior of 'return chasing' hurts individual investors the most and leads to poor resource allocation.
The most under-discussed lesson from the LTCM collapse was not firm-level leverage, but the personal failure of its partners to apply a robust risk framework (like expected utility) when deciding how much of their own wealth to invest in their fund.
John Bogle's wisdom holds that the optimal investment strategy isn't based on historical performance but on what deeply resonates with your core beliefs. This ensures you'll stick with it during inevitable downturns, preventing the performance-destroying behavior of return chasing.
The optimal level of diversification is the maximum you can achieve at a very low cost. Investors should stop diversifying when the marginal benefit is outweighed by significantly higher fees, such as moving from broad market ETFs (3bps) to private equity (400bps).
When successful macro traders played the 'Crystal Ball' game, they won not by trading constantly, but by being highly selective. They almost exclusively traded bonds and only acted on the few days where they perceived a high expected Sharpe ratio, avoiding action otherwise.
Despite the focus on LTCM being 'too big' or 'too leveraged' in 1998, the capital deployed in similar relative-value strategies today is 10 to 100 times larger, suggesting the industry has amplified, not learned from, the systemic risks of scale and leverage.