Stick-With-It Investment Philosophy
Choose a durable philosophy and stay invested through market cycles
- Difficulty
- Moderate
- Time to result
- ~ongoing to results
- Steps
- 6
- Confidence
- 97%
This framework begins with a concrete financial objective, translates that objective into an appropriate asset mix, and anchors the portfolio to a philosophy the investor understands. The mechanism is behavioral as much as financial: when markets fall, the investor reviews why the allocation was chosen instead of treating volatility as a signal to flee. Risk must be limited to a level the investor can emotionally and financially withstand, because an theoretically optimal portfolio is useless if it is abandoned under pressure. The framework therefore turns consistency into an investment advantage. It also shifts attention away from market forecasts, recent winners, and all-time-high anxiety toward controllable decisions such as saving, diversification, allocation, and disciplined rebalancing.
Origin
Extracted from Masters in Business, where David Booth described how Dimensional clients maintained a consistent philosophy and stayed invested through the 2007-2009 crisis.
Core principles
- 01A usable philosophy matters more than a compelling forecast
- 02Market declines are normal rather than evidence that a plan has failed
- 03Risk exposure should remain within the investor's emotional capacity
- 04Consistency prevents destructive performance chasing
- 05Investor behavior shapes the realized investment experience
How to run it
- 1
Define the objective
Specify what the money must accomplish, such as retirement income, education funding, or a house purchase. Include the relevant time horizon and spending requirement.
Pro tip Express retirement objectives as inflation-adjusted income rather than an abstract wealth target.
Watch out Different objectives require different risk profiles, so do not combine every goal into one undifferentiated portfolio.
- 2
Choose the asset mix
Translate the objective into an allocation among equities, bonds, and other suitable assets. Balance the required return against the risk the investor can sustain.
Pro tip Use broad diversification to avoid depending on a few securities or sectors.
Watch out Do not select an allocation solely because its recent return looks attractive.
- 3
Test emotional capacity
Estimate how the allocation could behave during a severe decline and decide whether that experience is tolerable. Reduce exposure before a crisis if the likely loss would trigger panic.
Pro tip Discuss historical drawdowns in both percentage and monetary terms.
Watch out Stated risk tolerance in a calm market may overestimate actual tolerance during a crash.
- 4
Document the philosophy
Write down why the allocation should work and what normal market behavior looks like. Define which events would and would not justify changing it.
Pro tip Keep the explanation simple enough to revisit under stress.
Watch out A collection of products without a coherent rationale is not an investment philosophy.
- 5
Review rather than react
When volatility rises, revisit the objective, allocation, and market principles. Rebalance when appropriate, but avoid forecasts and emotionally driven exits.
Pro tip Use an advisor or accountability partner to reinforce the plan during difficult periods.
Watch out Selling after a fall can convert temporary volatility into permanent loss.
- 6
Update only for real changes
Revise the plan when the objective, time horizon, cash-flow needs, or capacity for risk materially changes. Ignore changes driven only by headlines or recent performance.
Pro tip Schedule periodic reviews so decisions are not triggered exclusively by market turmoil.
Watch out Constantly replacing the philosophy defeats its behavioral value.
In the wild
During 2007-2009, Dimensional's clients experienced the same severe market decline as other equity investors. Booth says they reviewed the fundamentals of how markets work and maintained their approach rather than trying to forecast the bottom. While the broader industry suffered massive equity-fund outflows, Dimensional recorded positive flows each year.
→ Clients remained positioned for the subsequent recovery instead of locking in losses near the bottom.
An investor holds cash because the market is near a record and plans to buy after a crash. Prices continue rising, making entry feel progressively harder. Applying the framework, the investor defines a long-term allocation, phases the cash into that allocation, and accepts that short-term movements cannot be reliably controlled.
→ The investor replaces indefinite market timing with a sustainable long-term plan.
Common mistakes
Choosing the flavor of the month
Selecting funds or sectors because they recently performed well encourages investors to buy after gains and abandon them after reversals.
Taking more risk than you can endure
An aggressive allocation fails if ordinary market volatility causes the investor to panic and sell.
Treating philosophy as a forecast
A durable process accepts uncertainty; it does not depend on correctly predicting the next market move.
Is it for you?
Best for
It is best for long-term investors who need a disciplined way to withstand uncertainty and market volatility.
Not ideal for
It is not ideal for money needed imminently or investors whose portfolios exceed their genuine capacity for loss.
From the transcript
“The first key to investing is find a philosophy that you can stick with through thick and thin.”
“Markets are going to go up and down, that's what they do, and you shouldn't invest more in the market than you can. UH. Then…”
“It's the philosophy and a consistent approach so people can feel they need to not only have good returns, they need to feel good and…”
From the episode
Dimensional Fund CEO David Booth: Masters in Business (Audio)
David Booth