Week 39 Day 4: Greed: Fear's Mirror Image and Equally Destructive Twin

Fear makes you sell low. Greed makes you buy high. Together, they form a perfect wealth-destruction machine. The investor who panic-sold in March 2020 (fear) and piled into meme stocks and crypto in late 2021 (greed) experienced the worst of both: sold the good investment at the bottom and bought the bad investment at the top.

Greed's manifestations: (1) Performance chasing. The fund or stock that returned 50% last year attracts the most money this year. But high past returns often mean high current valuations and low future returns. Morningstar data: the top-performing fund category over the past 3 years is the worst-performing category over the next 3 years, on average. (2) Overconcentration. 'Why diversify? Tech stocks are the future!' Concentrating in the best-performing sector maximizes returns when that sector continues to outperform and maximizes losses when it means-reverts. From 2000-2002, the NASDAQ fell 78%. Diversified investors lost 40-50%. Concentrated tech investors lost everything. (3) Leverage. Greed borrows money. If stocks return 10% and you borrow at 5%, you earn 15% on your equity! But if stocks fall 30%, your losses are amplified and margin calls force you to sell at the worst possible time. Leverage turns temporary drawdowns into permanent losses. (4) Ignoring risk. Greed says 'the risk is worth it.' But greed evaluates risk based on recent returns (which were great) rather than on the underlying probability distribution (which includes crashes). Every bubble in history was fueled by the belief that 'this time is different' and that the old rules of risk no longer applied. Greed antidotes: (a) Diversification is mandatory, not optional -- even when some assets underperform. (b) Never use leverage in your long-term portfolio. (c) When an investment feels 'exciting,' that is a warning sign, not a buy signal. (d) Rebalance annually -- selling what went up and buying what went down is the systematic antidote to greed.

Greed in financial markets is modeled through overreaction and momentum: investors extrapolate recent positive returns into the future (representativeness heuristic, Tversky and Kahneman, 1974), leading to overbuying of recent winners. De Bondt and Thaler (1985) showed that stocks with the highest past 3-year returns (the 'greed targets') subsequently underperform by approximately 8% per year, consistent with reversion from overreaction-driven overvaluation. At the aggregate level, Shiller's (2000) cyclically adjusted price-earnings (CAPE) ratio provides a greed gauge: when CAPE exceeds 30 (approximately the 90th percentile historically), subsequent 10-year returns average approximately 3-4%, versus approximately 10-12% when CAPE is below 15. Greed (buying at high valuations) systematically reduces future returns. The leverage amplification of greed is formalized in Brunnermeier and Pedersen (2009): leverage creates a feedback loop where rising prices increase collateral value, enabling more borrowing, enabling more buying, further increasing prices -- until the loop reverses (a 'Minsky moment'). The reversal triggers margin calls, forced selling, and price crashes that exceed fundamental-based declines by 2-5x. Historical examples: LTCM (1998, leverage 25:1, lost 92%), the 2008 financial crisis (bank leverage 30-50:1, systemic collapse), and crypto leverage in 2022 (Luna/Terra, 3AC, FTX, all leveraged, all collapsed). For individual investors, the no-leverage rule is absolute: the expected marginal return from leverage (approximately 3-5% under favorable assumptions) is dominated by the expected cost of the tail-risk event (margin call during a crash, forcing crystallization of temporary losses into permanent ones).