Active Manager Selection Rule
Choose differentiated, low-fee managers and hold them through normal performance cycles.
- Difficulty
- Moderate
- Time to result
- ~ongoing to results
- Steps
- 7
- Confidence
- 93%
The rule rejects both blanket faith in active management and blanket dismissal based on average results. First, the investor verifies that the manager is genuinely active rather than charging active fees for a benchmark-like portfolio. Next, the investor evaluates whether the manager has a coherent philosophy, a repeatable process, a sufficiently long horizon, and an identifiable source of advantage. Fees receive special emphasis because they are certain while excess returns are not. The evaluation period must match the strategy's horizon; otherwise normal short-term noise will be mistaken for evidence of skill or failure. Once a suitable manager is selected, the investor commits to staying through inevitable performance cycles unless the process, people, incentives, or mandate materially changes.
Origin
Extracted from Masters in Business during Tom Slater's discussion of active share, manager differentiation, fees, and long-term client behavior.
Core principles
- 01A genuinely active manager must be willing to differ from the index.
- 02Philosophy and process matter more than the average active-manager result.
- 03Longer time horizons improve the chance that differentiated judgment can add value.
- 04Fees are one of the few investment outcomes known with certainty.
- 05A suitable manager must be retained through inevitable periods of underperformance.
How to run it
- 1
Verify genuine activity
Measure how substantially the portfolio and decisions differ from the stated benchmark.
Pro tip Inspect holdings, concentration, turnover, and active share together.
Watch out A fund can market itself as active while maintaining extensive index overlap.
- 2
Understand the philosophy
Require a clear explanation of what opportunities the manager pursues and why the approach should work.
Pro tip Ask what the manager deliberately refuses to do.
Watch out Broad claims about research quality are not a differentiated philosophy.
- 3
Inspect the process
Determine how ideas are generated, evaluated, sized, monitored, and sold, and whether those actions match the stated philosophy.
Pro tip Use historical decisions to test whether the process is actually followed.
Watch out A compelling philosophy without consistent implementation has little value.
- 4
Identify the manager's edge
Ask what structural, informational, analytical, or behavioral advantage the team possesses over competitors.
Pro tip Favor an edge supported by organizational design and evidence.
Watch out Past returns alone do not explain why an advantage should persist.
- 5
Control certain costs
Compare all-in fees with the potential value of the differentiated strategy.
Pro tip Judge results net of every recurring charge.
Watch out High fees compound even when performance disappoints.
- 6
Set a suitable evaluation horizon
Assess performance over a period commensurate with the manager's stated investment process.
Pro tip Define the review horizon before recent returns influence the decision.
Watch out One-year results are often dominated by noise.
- 7
Stay through ordinary cycles
Retain the manager during normal underperformance unless there is evidence that the philosophy, process, personnel, or incentives have changed.
Pro tip Maintain written firing criteria to distinguish patience from inertia.
Watch out Commitment should not excuse style drift, hidden risk, or a broken process.
In the wild
A saver compares a low-cost index fund with a concentrated active growth fund. The active fund passes only if its holdings differ materially from the index, its long-horizon process is coherent, its behavioral edge is credible, and fees remain reasonable. The saver then evaluates it over a multi-year period and does not abandon it after one weak year.
→ The active allocation is both genuinely differentiated and behaviorally sustainable.
Common mistakes
Paying active fees for index overlap
Closet indexing preserves the manager's business risk while giving clients little differentiated return potential.
Judging a long strategy annually
A one-year result can be dominated by noise and may not reveal whether the manager's process has skill.
Performance chasing
Hiring after outperformance and firing during an inevitable weak cycle can destroy the benefit of selecting a sound long-term manager.
Is it for you?
Best for
It is best for long-horizon investors considering an active fund alongside low-cost passive alternatives.
Not ideal for
It is not ideal for investors unwilling to tolerate benchmark divergence or unable to evaluate a manager's process.
From the transcript
“Now, it's it's it's important that you have clarity around philosophy, process, what you're actually trying to do, and it's it's centrally important that your…”
“Do they keep their fees to a minimum so that you as an individual have to have the best chance of our performing because the…”
“If little changes, then stick with them through inevitable performance cycles.”
From the episode
Tom Slater on Growth Investing (Podcast)
Tom Slater