Active Management, Information Ratio, and the Fundamental Law

How Level II tests value added, active risk, information ratio, and the fundamental law of active portfolio management.

Level II active-management questions are usually about whether skill is being converted into value added efficiently. The exam is not just asking whether a manager beat a benchmark. It is asking how that excess return relates to active risk, forecast skill, implementation efficiency, and breadth.

Why This Lesson Matters

Candidates often overfocus on return and underfocus on how the return was earned. That is exactly what the information ratio and the fundamental law are designed to prevent.

Value Added Must Be Read Relative To Active Risk

The ex post information ratio is commonly expressed as:

$$ \text{IR} = \frac{R_P - R_B}{\sigma(R_P - R_B)} $$

MeasureWhat it answers
Active returnDid the portfolio outperform the benchmark?
Active risk or tracking riskHow much benchmark-relative risk did it take to do so?
Information ratioHow efficiently did the manager convert active risk into value added?

That is why a manager with lower active return can still be better if the active-risk usage is much more disciplined.

Sharpe Ratio And Information Ratio Are Not The Same Job

MeasureBest use
Sharpe ratioEvaluate return per unit of total risk
Information ratioEvaluate benchmark-relative value added per unit of active risk

Level II often tests whether the benchmark-relative question is the real one.

A common form of the fundamental law is:

$$ \text{IR} \approx \text{TC} \times \text{IC} \times \sqrt{\text{BR}} $$

ComponentWhat it means
Transfer coefficient (TC)How efficiently portfolio construction converts forecasts into positions
Information coefficient (IC)Forecast skill
Breadth (BR)Number of independent opportunities

This matters because strong insight does not automatically become strong portfolio results if the manager cannot express it cleanly or if true opportunity breadth is low.

Breadth Is Not Just “More Trades”

Candidates often overstate breadth by counting every signal or position as independent. The stronger interpretation asks whether the opportunities are genuinely distinct.

SituationLikely interpretation
Many highly correlated betsBreadth is lower than it first appears
Few but genuinely independent decisionsBreadth may be more useful than a larger but redundant signal set
Tight constraints or benchmark limitsTransfer coefficient can fall even with strong IC

Level II is often testing that qualitative judgment rather than a pure plug-and-chug formula.

Active Management Style Matters

Strategy typeCommon analytical question
Security selectionIs stock-picking skill producing benchmark-relative value added?
Market timingIs the manager changing systematic exposure effectively?
Mixed approachAre changes in style increasing active risk without improving efficiency?

The exam may ask whether a strategy change improved expected information ratio or just increased aggressiveness.

How CFA-Style Questions Usually Test This

  • by asking whether information ratio or Sharpe ratio is the better evaluation tool
  • by asking how a change in breadth, IC, or transfer coefficient affects expected IR
  • by describing a constrained manager whose forecasts are not fully expressed in the portfolio
  • by asking whether a strategy change improved efficiency or simply raised active risk

Mini-Case

A manager introduces more ideas, but the new signals are highly correlated and benchmark constraints prevent large active weights. A weak answer assumes expected IR rises because breadth rose.

A stronger answer questions whether true independent breadth increased and whether the transfer coefficient may actually have fallen.

Common Traps

  • treating active return alone as proof of skill
  • using Sharpe ratio when the benchmark-relative question is central
  • counting correlated bets as independent breadth
  • assuming skill matters more than implementation efficiency

Sample CFA-Style Question

Which change is most likely to increase expected information ratio if forecast skill is unchanged?

Best answer: An increase in transfer coefficient that allows forecasts to be translated into portfolio positions more effectively.

Why: Level II often tests whether you understand that portfolio construction friction can block value added even when research quality is solid.

Continue In This Chapter

Revised at Thursday, April 9, 2026