Solved-Problem Investing
Build around your goals, diversify cheaply, rebalance, and avoid costly mistakes.
- Difficulty
- Easy
- Time to result
- ~ongoing to results
- Steps
- 6
- Confidence
- 96%
Solved-Problem Investing separates portfolio construction from the harder behavioral and planning questions surrounding it. First, define what the money must accomplish, when it will be needed, how much risk is tolerable, and which tax or account constraints apply. Then select a broad, low-cost portfolio whose expected risk pattern fits those requirements; a target-date fund or diversified set of index ETFs can handle most of this work. Specialized assets or active managers are optional refinements rather than the foundation. Rebalance periodically and resist panic selling, valuation-based market timing, and other unforced errors. The mechanism works by using diversification to manage uncertainty while reducing the number of emotional decisions that can interrupt compounding.
Origin
Extracted from Masters in Business, where Dave Kndig argues that portfolio mathematics is largely solved and investor effort should shift toward goals, behavior, and risk management.
Core principles
- 01Start with the purpose of the money, not investment products.
- 02Match portfolio risk to the goal, time horizon, and investor.
- 03Use broad diversification and low costs for the portfolio core.
- 04Treat complexity as optional fine-tuning, not a prerequisite.
- 05Protect returns by avoiding panic, market timing, and other unforced errors.
How to run it
- 1
Define the destination
Specify how much money is available, what it must fund, and when it will be needed. Turn investing from an abstract search for returns into a concrete planning problem.
Pro tip Express the objective as an amount and date, such as funding college costs in fifteen years.
Watch out Do not select investments before clarifying what the portfolio must accomplish.
- 2
Map personal constraints
Assess risk tolerance, tax circumstances, liquidity needs, and account options. These inputs determine which return pattern is suitable.
Pro tip Consider whether tax-advantaged accounts such as a 529 or retirement plan fit the goal.
Watch out A mathematically efficient portfolio can still be unsuitable if the investor cannot tolerate its losses.
- 3
Build the diversified core
Use a target-date fund or globally diversified portfolio of broad, low-cost index funds. Match the equity and bond allocation to the goal and time horizon.
Pro tip Favor simple funds that make concentrated bets and impulsive changes harder.
Watch out Do not mistake additional complexity for a reliably better portfolio.
- 4
Constrain optional refinements
If desired, allocate a limited portion to active bonds, commodities, cryptocurrency, real estate, or other specialized exposures. Treat these as fine-tuning rather than the source of core returns.
Pro tip Keep the diversified core responsible for roughly 80–90 percent of the portfolio.
Watch out Specialized assets introduce additional risks and should not displace the core without a goal-based reason.
- 5
Rebalance on schedule
Choose an annual, quarterly, or otherwise appropriate schedule for restoring the intended allocation. Apply it consistently rather than reacting to headlines.
Pro tip Annual rebalancing is a simple default for investors who do not need tighter controls.
Watch out Do not turn rebalancing into discretionary market timing.
- 6
Avoid unforced errors
Remain invested through volatility and evaluate decisions by the quality of the process. Change the portfolio when goals or constraints change, not merely because sentiment or prices moved.
Pro tip Write down the investment policy so stressful markets do not redefine it.
Watch out Panic selling and sitting out anticipated declines can remove much of an individual investor's return.
In the wild
An investor has one hundred thousand dollars intended for a child's college expenses in fifteen years. After considering risk tolerance, taxes, and whether a 529 account is available, the investor selects an appropriately dated target-date fund rather than trying to forecast sectors or choose winning stocks.
→ The portfolio automatically adjusts its risk as the spending date approaches while keeping the investor focused on the college goal.
A long-term investor holds a globally diversified set of broad, low-cost equity and bond ETFs. The allocation is rebalanced once each year, while a small optional sleeve provides limited exposure to real estate or commodities without disrupting the core plan.
→ Most market exposure is captured cheaply while the rules reduce opportunities for emotional trading.
Common mistakes
Choosing products before defining the goal
Starting with stocks, sectors, or funds ignores the time horizon, tax situation, liquidity needs, and risk tolerance that should shape the portfolio.
Chasing the final ten percent
Investors may add complexity and risk while trying to improve a diversified portfolio that already delivers most of what they need.
Reacting to market sentiment
Selling after declines or waiting outside the market because prices appear expensive can cause investors to miss recoveries and rallies.
Is it for you?
Best for
It is best for long-term investors who want a robust portfolio without continuously forecasting markets or selecting securities.
Not ideal for
It is not ideal for investors seeking guaranteed returns, frequent trading, or highly concentrated speculative exposure.
From the transcript
“Once you've answer all of those questions, then constructing that portfolio, what do I own to get a pattern of returns deliver me the maximum…”
“For most people, as you said, a diversified portfolio of low cost indexed ETFs is going to get you ninety percent of the way there.”
“Making the decision to do that and then sticking with it is the difficult part.”
From the episode
At the Money: The Right And Wrong Way to Invest