Factor Investing
Factor investing selects assets based on characteristics — such as value, size, momentum, quality or low volatility — that have historically been linked to returns. Smart-beta funds package these factors in rules-based portfolios.
Why do some stocks outperform over long periods? Research found that certain traits, or factors, explain much of the difference: cheap stocks, small companies, stocks with momentum, high-quality firms. Factor investing tilts portfolios toward those traits on purpose. This entry explains the main factors, how factor funds work and the risks of chasing them.
- Category
- Trading Strategies
- Reading time
- 3 min
- Also called
- Smart beta, Style investing, Factor-based investing
- Updated
Factor investing in plain words
Factor investing chooses assets based on a defined set of factors or attributes.1
Two broad types of factors have historically been linked to returns: style factors and macroeconomic factors.1
Smart-beta strategies use rules to target such characteristics, sitting between pure index tracking and active management.2
How to build a factor portfolio, step by step
Choose factors
Value, size, momentum, quality, low volatility.
Define rules
E.g. cheapest 30% by P/E. See Price-to-Earnings Ratio.
Screen the universe
Rank stocks by each factor.
Weight holdings
Equal, cap or factor-score weighted. See Index Weighting.
Rebalance regularly
Factors change over time. See Rebalancing.
Monitor costs
Turnover can eat the premium.
Worked examples
Example 1 — Value screen
Cheapest 20%From 500 stocks, a fund buys the 100 with the lowest price-to-book ratios.
| Selected share | 100 ÷ 500 = 20% |
Factor investors identify characteristics they want and select stocks that show them.1 See Growth vs Value Stocks.
Example 2 — A factor premium
≈ +$2,085Over 10 years the value portfolio returns 9% a year vs 8% for the market.
| Premium | +1 point a year |
| On $10,000 | $23,674 vs $21,589 |
Small yearly premiums compound into meaningful differences — when they show up. See Compound Interest.
Example 3 — Factor drought
Long drawdownThe same factor underperforms the market by 2 points a year for 5 years.
| Cumulative lag | ≈ −10 points |
Factors can lag for years, testing investors' patience. See Behavioral Finance.
Common style factors
| Aspect | Targets | Risk |
|---|---|---|
| Value | Cheap stocks | Value traps |
| Size | Small companies | Higher volatility |
| Momentum | Recent winners | Sharp reversals |
| Quality | Profitable, stable firms | Can be expensive |
How investors use factors
Smart-beta ETFs
Rules-based factor funds. See Exchange-Traded Fund.
Explaining performance
How much was factor exposure, not skill? See Alpha.
Diversification
Combining factors that behave differently.
Market-neutral funds
Long high-factor, short low-factor stocks. See Market-Neutral Strategies.
Advantages and disadvantages
Advantages
- Evidence-based approach.
- Rules make it transparent.
- Cheaper than most active management.
Disadvantages
- Premiums are not guaranteed.
- Long underperformance periods.
- Crowding can erode returns.
Going deeper
Read as far as you need. Each level builds on the one before it.
Choosing characteristics
Beginner
Investors following a factor approach first identify the characteristics they want in a stock.1
Factors vs alpha
Intermediate
Beyond CAPM
Advanced
Multi-factor models extend CAPM's single market factor with size, value, momentum and others to explain returns better. See Capital Asset Pricing Model.
Common mistakes
Chasing last year's best factor
Leadership rotates.
Ignoring overlap
Factors can be correlated.
Underestimating costs
High-turnover factors are expensive.
Data mining
Many "factors" don't survive testing. See Data Snooping.
Check your understanding
Test yourself before moving on. Each answer comes with an explanation.
Key points to remember
- Factor investing targets traits linked to returns.
- Common factors: value, size, momentum, quality, low volatility.
- Smart-beta funds apply factors with rules.
- Premiums are uncertain and cyclical.
- Costs and crowding matter.
Frequently asked questions
Is smart beta the same as factor investing?
Which factor is best?
Do factors work in crypto?
Further learning
- Growth vs Value Stocks
The value factor.
- Momentum
The momentum factor.
- Capital Asset Pricing Model
The single-factor model.
- Alpha
Separating skill from factors.
Sources
This article is written in our own words. The sources below support the specific facts, rules and figures marked with a number in the text. Links open the original publisher’s page.
- Corporate Finance Institute. Factor Investing (opens in a new tab) Checked .
- Fidelity. Alpha, Beta, and Smart Beta (opens in a new tab) Checked .
Educational content, not financial advice. Examples use hypothetical prices and simplified costs; actual fees, margin rules and regulations vary by broker, market and country. We are not affiliated with any publisher linked above. Last reviewed . Report an error or request a source credit.