The Sharpe ratio measures return earned per unit of risk — the most cited yardstick of risk-adjusted performance. What it captures well, and its four blind spots: it treats gains and losses alike, assumes well-behaved returns, can be inflated by smoothed prices, and stays a noisy estimate. Why a high ratio is a good question, never a verdict.
Jul 18, 2026 · 10 min read
Rebalancing returns a portfolio to its target weights to hold the risk you chose — not to chase return. Why its first job is risk control, where the conditional "rebalancing bonus" comes from, what spreads and stamp duty cost, and how to choose between a calendar rule and a tolerance band.
Jul 18, 2026 · 9 min read
"Risk" means three different things — volatility, drawdown, and permanent loss of capital. Why they sometimes diverge, why only the last one truly ends portfolios, and how leverage and forced selling turn a temporary decline into an unrecoverable loss.
Jul 18, 2026 · 9 min read
Every foreign asset hides a second bet: the currency. For a Swiss investor, the franc — strong and safe-haven — tends to rise when markets fall. What hedging does, why it costs roughly the interest-rate differential, and why foreign bonds are usually hedged but equities are a judgment call.
Jul 18, 2026 · 9 min read
Lose 50% then gain 50% and you are left with 75%, not par. Why the average of yearly returns always overstates real growth, how volatility is paid for in compound return, and why stability is worth strictly more than choppiness at an equal average return.
Jul 18, 2026 · 8 min read
Management fees, transaction costs, spread, stamp duty, custody: an investment's cost stacks in layers, several of which appear on no fact sheet. Why one fee too many costs not one point but nearly a third of final capital over thirty years — and why cost is the one variable an investor truly controls.
Jul 18, 2026 · 8 min read
A benchmark is not a neutral thermometer, it is a rule: a way of selecting, weighting, and maintaining a basket of securities. How cap-weighting, free float, dividends, and rebalancing decide what an index measures — and why “beating the market” is, before costs, a zero-sum game.
Jul 18, 2026 · 8 min read
Finance's only "free lunch," taken seriously: what correlation does to risk, why 4% of stocks created all the market's wealth, how many independent bets a portfolio really contains — and why the protection fades precisely in crashes.
Jul 17, 2026 · 9 min read
Factors, z-scores, deciles, the information coefficient: how a quantitative equity rating is built, why it is a relative ranking rather than a forecast — and the five questions that separate a disciplined score from a decorative number.
Jul 17, 2026 · 10 min read
Survivorship bias, data ahead of its publication date (a 73-day median publication lag across the reports in our database with a recorded release date), overfitting, forgotten costs, the single regime: why simulated curves outshine reality, and the questions that expose them.
Jul 17, 2026 · 9 min read