Investment risk encompasses more than price volatility. Market risk (systematic risk) affects all securities when the broad economy contracts or when interest rates shift. Credit risk is the possibility that a bond issuer defaults. Liquidity risk is the inability to exit a position at or near the quoted price — small-cap stocks, high-yield bonds, and private assets carry significant liquidity risk. Inflation risk erodes the purchasing power of fixed cash flows, devastating the real return of nominal bonds in inflationary environments. Concentration risk magnifies the impact of a single company or sector underperforming.

Sequence-of-returns risk is particularly critical for investors withdrawing from portfolios (retirees). Two portfolios with identical average annual returns can produce radically different terminal wealth if the timing of losses differs. A -40% loss in year one of retirement, followed by 15 years of 10% gains, produces far less terminal wealth than the reverse sequence — even though the arithmetic average return is identical. The devastating early loss depletes principal before recovery gains can compound on a full base. This is why retirement portfolio construction requires different risk management than accumulation-phase portfolio construction.

Capital market theory distinguishes between risks that earn a risk premium and those that do not. Systematic market risk (beta) earns the equity risk premium — approximately 4-6% annually above risk-free rates over long histories. Factor exposures (value, size, momentum, quality) earn documented factor premiums. These are compensated risks — bearing them is expected to generate excess return over time. Idiosyncratic (company-specific) risk is uncompensated — it can be diversified away at no cost, so the market offers no expected return for bearing it. Holding a concentrated stock position rather than a diversified portfolio means bearing uncompensated risk.

Liquidity risk occupies an interesting middle position. Private equity, real estate, and other illiquid assets carry a liquidity premium — expected returns above comparable public market exposures, in exchange for the inability to exit quickly. Whether the illiquidity premium actually compensates investors fully for the locked-up capital, governance disadvantages, and J-curve effects of private investments is debated, but the premium exists empirically. Investors with genuinely long time horizons (endowments, pension funds, sovereign wealth funds) can rationally capture this illiquidity premium; individual investors with uncertain liquidity needs are more cautious about locking up capital.

Risk management begins with understanding the full distribution of outcomes, not just the expected return. Key risk metrics: standard deviation (average magnitude of return variation), maximum drawdown (worst peak-to-trough decline), beta (sensitivity to market movements), Value at Risk (worst expected loss at a given confidence level), and Conditional VaR (expected loss given that VaR is exceeded). Each metric captures a different dimension of risk; no single measure is sufficient.

Practical risk management combines position sizing (ensuring no single bet can cause catastrophic portfolio damage), diversification (eliminating idiosyncratic risk), correlation monitoring (ensuring assets are genuinely diversifying rather than falsely appearing uncorrelated in calm markets), and stress testing (modeling portfolio behavior in historical crises: 2008, 2020, the dot-com crash). AIQ's risk scoring framework incorporates volatility, drawdown history, beta, and correlation metrics to give each stock a risk assessment that complements its momentum and fundamental signal.