Factor Investing Glossary

The excess return of an investment relative to the return predicted by a benchmark or factor model. Positive alpha indicates outperformance after adjusting for systematic risk exposures. In the context of factor models, alpha represents the portion of returns not explained by factor exposures, often interpreted as evidence of manager skill or unexploited market inefficiency.

Example: If a fund returns 12% when its factor exposures predict 10%, it has alpha of 2%.

A measure of systematic risk that quantifies the sensitivity of an asset's returns to movements in a benchmark or factor. Market beta measures sensitivity to the overall stock market. In multi-factor models, each factor has its own beta coefficient indicating the portfolio's exposure to that factor.

Example: A stock with beta of 1.5 is expected to move 1.5% for every 1% move in the market.

The ratio of a company's book value of equity to its market value of equity. High B/M ratios indicate "value" stocks trading at low prices relative to their accounting book value. Low B/M ratios indicate "growth" stocks trading at premiums to book value. This ratio is central to the Fama-French value factor (HML).

Example: A company with $100M book value and $200M market cap has B/M of 0.5.

The foundational asset pricing model developed by William Sharpe (1964), John Lintner (1965), and Jan Mossin (1966). CAPM posits that an asset's expected return is determined solely by its systematic risk exposure (beta) to the market portfolio. The Fama-French models extend CAPM by adding additional factors.

Example: With risk-free rate of 3%, market premium of 6%, and beta of 1.2, expected return is 3% + 1.2 × 6% = 10.2%.

The investment factor in the Fama-French Five-Factor Model. CMA measures the return difference between companies that invest conservatively (low asset growth) and those that invest aggressively (high asset growth). Historically, conservative firms have outperformed aggressive firms on a risk-adjusted basis.

Example: If conservative firms return 10% and aggressive firms return 7%, CMA = 3%.

A statistical measure of the linear relationship between two variables, ranging from -1 (perfect negative correlation) to +1 (perfect positive correlation). In factor analysis, correlations between factors are important for understanding diversification benefits and potential multicollinearity issues.

Example: Value (HML) and Momentum (UMD) factors have historically shown negative correlation.

The peak-to-trough decline in the value of an investment before a new peak is reached. Maximum drawdown represents the largest such decline over a specified period. Factor premiums can experience significant drawdowns lasting years or even decades, testing investor patience.

Example: The value factor experienced a drawdown of over 50% relative to growth during 2017-2020.

The excess return that investing in the stock market provides over a risk-free rate. This is the compensation investors receive for bearing the risk of equity investments. Also known as the market risk premium, it forms the basis of the market factor (Mkt-RF) in factor models.

Example: Historically, U.S. stocks have delivered roughly 5-7% annual premium over Treasury bills.

A characteristic or attribute that explains differences in returns across securities. Factors capture systematic sources of risk and return that affect broad groups of stocks. Common factors include market, size, value, momentum, profitability, and investment. Factor investing involves constructing portfolios to gain exposure to these characteristics.

Example: Size is a factor because small stocks have historically behaved differently from large stocks.

The sensitivity or loading of a portfolio or security to a particular factor. High factor exposure means the asset's returns are highly correlated with that factor's returns. Factor exposures are measured through regression analysis and expressed as beta coefficients.

Example: A value-tilted portfolio might have HML exposure of 0.5, meaning it captures 50% of the value factor.

The average return earned by a factor over time. Factor premiums represent compensation for systematic risk or the exploitation of market inefficiencies. Not all periods deliver positive factor premiums; factors can underperform for extended periods before reverting to their long-term averages.

Example: The historical value premium (HML) has averaged approximately 3-4% annually since 1926.

An extension of the three-factor model introduced in 2015 that adds profitability (RMW) and investment (CMA) factors. This model explains even more return variation and better captures patterns related to corporate profitability and investment behavior.

An asset pricing model developed by Eugene Fama and Kenneth French in 1993 that extends CAPM by adding size (SMB) and value (HML) factors to the market factor. The model explains significantly more of the cross-sectional variation in stock returns than CAPM alone.

Example: A small value stock might have high loadings on both SMB and HML factors.

Stocks with low book-to-market ratios, indicating they trade at high prices relative to their book value. Growth stocks typically have high expected future growth rates and often reinvest earnings rather than paying dividends. They represent the opposite end of the value spectrum from value stocks.

Example: Technology companies like those in the NASDAQ often exhibit growth stock characteristics.

The value factor in Fama-French models. HML measures the return spread between stocks with high book-to-market ratios (value stocks) and stocks with low book-to-market ratios (growth stocks). A positive HML return means value stocks outperformed growth stocks that period.

Example: If value stocks return 15% and growth stocks return 10%, HML = 5%.

The total market value of a company's outstanding shares, calculated by multiplying the current stock price by the number of shares outstanding. Market cap is the basis for size classification in factor models (small-cap vs. large-cap) and for constructing cap-weighted indices.

Example: A company with 100 million shares at $50/share has market cap of $5 billion.

The market risk premium in factor models, representing the excess return of the broad stock market over the risk-free rate. This is the original factor from CAPM and remains the most important factor in explaining stock returns.

Example: If the market returns 10% and T-bills yield 2%, Mkt-RF = 8%.

The tendency for stocks that have performed well recently to continue performing well, and stocks that have performed poorly to continue underperforming. While not part of Fama-French models, momentum (UMD or WML) is a well-documented factor often used alongside Fama-French factors.

Example: Stocks in the top decile of 12-month returns often continue outperforming over the next 3-12 months.

A measure of a company's profitability used in the Fama-French Five-Factor Model. It is calculated as revenues minus cost of goods sold, selling, general and administrative expenses, and interest expense, divided by book equity. High operating profitability indicates efficient operations.

A statistical measure indicating what percentage of historical observations fall below a given value. In factor analysis, percentile ranks help contextualize current factor values relative to history. A value at the 10th percentile is lower than 90% of historical observations.

Example: If today's value spread is at the 95th percentile, it means value stocks are cheaper than 95% of history.

The theoretical return on an investment with zero risk, typically proxied by U.S. Treasury bill yields. The risk-free rate is subtracted from other returns to calculate excess returns and risk premiums in factor models.

Example: Short-term Treasury bills yielding 5% serve as the risk-free rate baseline.

The profitability factor in the Fama-French Five-Factor Model. RMW measures the return difference between companies with robust (high) operating profitability and those with weak (low) profitability. Profitable companies have historically outperformed unprofitable ones.

Example: If highly profitable firms return 12% and unprofitable firms return 8%, RMW = 4%.

A method of analyzing returns over overlapping periods of a fixed length, such as rolling 12-month or 36-month returns. Rolling returns provide a more complete picture of performance variability than point-to-point returns and help visualize how factor premiums evolve over time.

Example: Rolling 10-year HML returns show periods of both strong outperformance and underperformance.

A measure of risk-adjusted return calculated as excess return divided by standard deviation. Higher Sharpe ratios indicate better return per unit of risk. Factor premiums can be evaluated by their Sharpe ratios to assess risk-adjusted attractiveness.

Example: A factor with 5% excess return and 10% volatility has Sharpe ratio of 0.5.

The historical tendency of small-capitalization stocks to outperform large-capitalization stocks over long periods. This premium is captured by the SMB factor in Fama-French models. The size premium has been weaker in recent decades compared to historical averages.

Example: Small-cap stocks have historically outperformed large-caps by roughly 2-3% annually.

The size factor in Fama-French models. SMB measures the return spread between small-capitalization stocks and large-capitalization stocks. A positive SMB return indicates small stocks outperformed large stocks that period.

Example: If small-caps return 12% and large-caps return 8%, SMB = 4%.

A measure of the dispersion or volatility of returns around their mean. Higher standard deviation indicates greater variability and uncertainty. In finance, standard deviation is commonly used as a proxy for risk.

Example: Annual stock market returns have historical standard deviation of about 15-20%.

The historical tendency of value stocks (high book-to-market) to outperform growth stocks (low book-to-market) over long periods. This premium is captured by the HML factor. The value premium has been highly variable, with extended periods of underperformance.

Example: Historically, value stocks have outperformed growth by approximately 3-4% annually.

The difference in valuation between value and growth stocks, typically measured using metrics like book-to-market, price-to-earnings, or price-to-cash flow. Wide value spreads indicate value stocks are unusually cheap relative to growth, potentially signaling higher expected future value premium.

Example: When value spreads reach extreme percentiles, subsequent value returns have historically been above average.

Stocks with high book-to-market ratios, indicating they trade at low prices relative to their fundamental value. Value stocks are often mature companies, cyclical businesses, or firms facing temporary challenges. They have historically delivered higher returns than growth stocks over long periods.

Example: Banks, utilities, and industrial companies often exhibit value stock characteristics.

A measure of the variation in an asset's price or returns over time. Higher volatility indicates greater uncertainty and is often associated with higher risk. Factor premiums exhibit volatility, meaning their returns vary significantly from period to period.

Example: The VIX index measures implied volatility of S&P 500 options.

A standardized measure indicating how many standard deviations an observation is from the mean. Z-scores allow comparison across different metrics and time periods. In factor analysis, z-scores help identify when factor valuations are at extreme levels.

Example: A z-score of +2 means the value is 2 standard deviations above the historical average.