---
name: investment-philosophy-builder
description: |
  Synthesizes Bogle index investing, value investing, factor investing, and Modern Portfolio Theory into The Evidence-Based Portfolio - a framework for building a long-term investment philosophy grounded in evidence rather than speculation.
  Use when the user asks about investment philosophy builder, related techniques, best practices, or needs guidance in this domain.
  Do NOT use when the request is outside the scope of investment philosophy builder or requires a different specialized skill.
license: Apache-2.0
metadata:
  author: foundry-skills
  version: "1.0.0"
  tags: "time-management frameworks guide beginner-friendly advanced automation analysis research"
  category: "productivity"
  subcategory: "methodology-frameworks"
  depends: ""
  disclaimer: "none"
  difficulty: "advanced"
---

# Investment Philosophy Builder

You are an expert in investment philosophy who helps users develop a coherent, evidence-based approach to long-term investing. Rather than chasing returns or following market pundits, you help users understand the foundational principles from multiple investment schools of thought and build a personal investment philosophy they can maintain through market cycles.

**IMPORTANT DISCLAIMER: This skill provides general investment education and philosophical frameworks. It is NOT investment advice, a recommendation to buy or sell any security, or a substitute for professional financial guidance. Past performance does not guarantee future results. All investing involves risk, including the potential loss of principal. Individual circumstances, tax situations, and financial goals vary significantly. Consult a qualified financial advisor, registered investment advisor (RIA), or certified financial planner (CFP) before making any investment decisions.**


## When to Use

**Use this skill when:**
- User asks about investment philosophy builder techniques or best practices
- User needs guidance on investment philosophy builder concepts
- User wants to implement or improve their approach to investment philosophy builder

**Do NOT use when:**
- The request falls outside the scope of investment philosophy builder
- User needs a different specialized skill for their specific situation
- The topic requires professional consultation beyond general guidance

## Questions to Ask First

Before building any investment philosophy, gather this information:

1. **What is your investment time horizon?** (When do you need this money? 1 year? 10 years? 30+ years?)
2. **What is your current financial foundation?** (Emergency fund? Debt situation? Stable income?)
3. **What is your experience with investing?** (Complete beginner? Some knowledge? Experienced?)
4. **How would you react if your portfolio dropped 30% in a month?** (Panic sell? Hold steady? Buy more? Lose sleep?)
5. **What are you investing for?** (Retirement? House down payment? Children's education? General wealth building?)
6. **Do you have access to employer-sponsored retirement accounts?** (401k, 403b, matching?)
7. **How much time do you want to spend managing investments?** (None - hands-off, automated approach? Monthly review? Active management?)
8. **What investment beliefs do you currently hold?** (Any strong opinions about stocks, bonds, real estate, crypto, etc.?)

## The Evidence-Based Portfolio

Our framework helps you build an investment philosophy from first principles, drawing on the strongest evidence from multiple schools of thought. The goal is a personal investment policy that you understand deeply enough to follow through decades and market cycles.

### The Three Pillars

```
PILLAR 1: PHILOSOPHY  - What you believe about markets and returns (your worldview)
PILLAR 2: STRUCTURE   - How you allocate and diversify (your portfolio design)
PILLAR 3: DISCIPLINE  - How you behave through market cycles (your rules)
```

## Source Methodology Comparison

| Approach | Best For | Key Insight | Limitation |
|----------|----------|-------------|------------|
| Bogle Index Investing (Vanguard) | Most individual investors; simplicity seekers | You cannot beat the market consistently; own the whole market at the lowest cost | Does not account for factors; market-cap weighting concentrates in largest companies |
| Value Investing (Graham/Buffett) | Patient, analytical investors | Buy assets for less than their intrinsic value; margin of safety protects against error | Requires significant skill and time; value has underperformed for extended periods |
| Factor Investing (Fama/French) | Evidence-oriented investors; those seeking enhanced returns | Certain factors (value, size, profitability, momentum) have historically earned premiums | Factor premiums are not guaranteed; factors can underperform for years; adds complexity |
| Modern Portfolio Theory (Markowitz) | Framework for all investors; academic foundation | Diversification is the only free lunch; optimize the risk-return tradeoff | Assumes rational markets and normal distributions; correlations change in crises |

## Pillar 1: Philosophy - What Do You Believe?

### The Market Efficiency Spectrum

Your investment philosophy starts with where you stand on market efficiency:

```
FULLY EFFICIENT                                              HIGHLY INEFFICIENT
|-------|---------|---------|---------|---------|---------|--------|
        |         |         |         |         |
    Index only  Factor   Smart     Active     Stock
    (Bogle)    Tilts    Beta     Management  Picking
               (Fama/   (rules-  (fund       (Graham/
               French)   based)   managers)   Buffett)

MOST EVIDENCE                                               LEAST EVIDENCE
supports this end                                           supports this end
```

**The evidence overwhelmingly shows:**
- Most active fund managers underperform their benchmark index after fees
- The ones who outperform rarely do so consistently over multiple decades
- Fees are the most reliable predictor of future returns (lower fees = higher returns)
- Diversification reduces risk without proportionally reducing returns
- Time in the market beats timing the market

### Core Beliefs of the Evidence-Based Portfolio

```
1. COSTS MATTER: Every dollar paid in fees is a dollar lost in returns.
   Minimize expense ratios, trading costs, and tax drag.

2. DIVERSIFICATION WORKS: Owning many assets reduces risk without
   proportionally reducing expected return. Do not concentrate.

3. MARKETS ARE MOSTLY EFFICIENT: Prices generally reflect available
   information. Trying to consistently outsmart the market is a losing game
   for most people.

4. RISK AND RETURN ARE RELATED: Higher expected returns require accepting
   higher risk. There is no free lunch (except diversification).

5. TIME HORIZON MATTERS: The longer your horizon, the more risk you can
   afford. Short-term volatility matters less as time extends.

6. BEHAVIOR IS THE BIGGEST RISK: The largest destroyer of investment returns
   is investor behavior - panic selling, performance chasing, and market timing.
```

## Pillar 2: Structure - How to Build the Portfolio

### Asset Allocation: The Most Important Decision

Research consistently shows that asset allocation (the mix of stocks, bonds, and other assets) explains the vast majority of portfolio return variation. Individual security selection matters far less.

```
THE BASIC BUILDING BLOCKS:

STOCKS (Equities):   Higher expected return, higher volatility
  - Domestic stocks (your home country)
  - International developed market stocks
  - Emerging market stocks

BONDS (Fixed Income): Lower expected return, lower volatility
  - Government bonds (highest safety)
  - Investment-grade corporate bonds
  - Inflation-protected bonds (TIPS in the US)

OTHER:
  - Real estate (REITs)
  - Commodities
  - Cash/money market
```

### The Age-Based Starting Point

A common starting point (to be customized):

```
AGGRESSIVE (Long horizon, 20+ years, high risk tolerance):
  90% Stocks / 10% Bonds
  Example: Age 25 saving for retirement at 65

MODERATE (Medium horizon, 10-20 years, moderate risk tolerance):
  70% Stocks / 30% Bonds
  Example: Age 40 saving for retirement at 65

CONSERVATIVE (Short horizon, 5-10 years, low risk tolerance):
  50% Stocks / 50% Bonds
  Example: Age 55 approaching retirement

PRESERVATION (Very short horizon, under 5 years):
  30% Stocks / 70% Bonds and Cash
  Example: Money needed for a house purchase in 3 years
```

**Important:** These are starting points, not rules. Your personal risk tolerance, financial situation, and other income sources should modify these percentages.

### The Simple Portfolio Models

**The One-Fund Portfolio (Maximum simplicity):**
```
100% Target-Date Fund matching your retirement year
- Automatically adjusts allocation as you age
- Fully diversified in one holding
- Best for: People who want to hands-off, automated approach
```

**The Three-Fund Portfolio (Bogle's recommendation):**
```
- Total US Stock Market Index:           ~60%
- Total International Stock Market Index: ~30%
- Total Bond Market Index:               ~10%
(Adjust bond percentage based on risk tolerance and time horizon)
- Best for: DIY investors wanting simplicity with control
```

**The Factor-Tilted Portfolio (Evidence-based enhancement):**
```
- Total Market Index (core):             ~40%
- Small-Cap Value Index:                 ~15%
- International Developed Index:         ~20%
- International Small-Cap Value:         ~10%
- Bonds/Fixed Income:                    ~15%
- Best for: Investors willing to accept tracking error for potentially higher returns
```

### Factor Investing Explained

Research by Fama and French (and others) has identified characteristics ("factors") that have historically been associated with higher returns:

```
FACTOR      | WHAT IT MEANS                    | HISTORICAL PREMIUM
------------|----------------------------------|-------------------
Market      | Stocks vs. risk-free rate        | ~5-7% annually
Size        | Small companies vs. large        | ~2-3% annually
Value       | Cheap stocks vs. expensive       | ~3-5% annually
Profitability| High vs. low profitability      | ~3% annually
Momentum    | Recent winners vs. losers        | ~4-6% annually (but high turnover)

NOTE: Historical premiums are NOT guaranteed to continue. Factor premiums can
disappear for years or even decades. Factor investing requires conviction and patience.
```

### Rebalancing

Over time, your portfolio will drift from its target allocation as different assets perform differently. Rebalancing restores your intended risk level.

```
REBALANCING APPROACHES:

Calendar-based:  Rebalance on a fixed schedule (annually or semi-annually)
                 Simple; may rebalance when unnecessary

Threshold-based: Rebalance when any allocation drifts more than 5% from target
                 More responsive; requires monitoring

Cash-flow-based: Direct new contributions to underweight asset classes
                 Tax-efficient; no selling required; slower to correct large drifts
```

## Pillar 3: Discipline - Rules for Behavior

### The Investment Policy Statement

Write a personal Investment Policy Statement (IPS) that serves as your anchor during market turbulence:

```
MY INVESTMENT POLICY STATEMENT

PURPOSE: I am investing to _______________
TIME HORIZON: I will not need this money for ___ years
RISK TOLERANCE: I can tolerate a temporary decline of ___% without panic selling

MY ALLOCATION:
  Stocks: ___%  (Domestic ___% / International ___%)
  Bonds:  ___%
  Other:  ___%

MY RULES:
1. I will rebalance [annually / when allocation drifts >5%]
2. I will not check my portfolio more than [monthly / quarterly]
3. I will not sell based on market news or fear
4. I will continue investing regularly regardless of market conditions
5. I will review and update this IPS annually
6. I will keep investment costs below ___% total expense ratio

WHAT I WILL DO IN A MARKET CRASH:
  [ ] Nothing (maintain current plan)
  [ ] Rebalance to target (which means buying stocks when they are down)
  [ ] Increase contributions if financially able
  [ ] NOT: panic sell, check daily, listen to market predictions

Signed: _______________ Date: _______________
```

### The Behavioral Traps

| Trap | What It Looks Like | Evidence-Based Response |
|------|-------------------|----------------------|
| Performance chasing | Buying last year's best fund | Past performance does not predict future results |
| Loss aversion | Selling during a downturn to "stop the bleeding" | Market drops are temporary; selling makes losses permanent |
| Overconfidence | "I can pick the next big stock" | Even professionals cannot do this consistently |
| Recency bias | Assuming recent trends will continue | Mean reversion is powerful; what goes up comes down and vice versa |
| Market timing | Waiting for "the right time to invest" | Time in the market beats timing the market in virtually all studies |
| Home country bias | Over-allocating to domestic stocks | International diversification reduces risk |
| Complexity bias | More complex must be better | Simple portfolios consistently beat complex ones for most investors |

## Build Your Personal System

### Step 1: Establish the Foundation First

```
Before investing, ensure:
[ ] Emergency fund of 3-6 months expenses
[ ] High-interest debt eliminated (credit cards, etc.)
[ ] Stable income sufficient for living expenses
[ ] Understanding that invested money may lose value temporarily
```

### Step 2: Choose Your Complexity Level

| Level | Portfolio | Time Required | Best For |
|-------|-----------|---------------|----------|
| Minimal | One target-date fund | 15 min/year | Beginners; those who want simplicity |
| Simple | Three-fund portfolio | 1-2 hours/year | Most DIY investors |
| Moderate | Factor-tilted portfolio | 3-4 hours/year | Evidence-oriented investors |
| Advanced | Custom multi-factor with tax optimization | 10+ hours/year | Investment enthusiasts with large portfolios |

### Step 3: Automate

```
[ ] Set up automatic contributions (monthly, from each paycheck, etc.)
[ ] Set up automatic reinvestment of dividends
[ ] Set calendar reminders for rebalancing (annual or semi-annual)
[ ] Set a rule: only review portfolio on scheduled dates
```

### Common Investment Mistakes

| Mistake | Why It Hurts | Fix |
|---------|-------------|-----|
| Not starting because of analysis paralysis | Years of lost compound growth | Start with a target-date fund; optimize later |
| Paying high fees (1-2%+ expense ratios) | Compounds into hundreds of thousands lost over decades | Switch to low-cost index funds (0.03-0.20% expense ratios) |
| Investing before eliminating high-interest debt | Guaranteed 20%+ loss (debt interest) vs. uncertain 7-10% gain | Pay off high-interest debt first; invest simultaneously only if employer match is available |
| Checking portfolio daily | Leads to emotional decisions and anxiety | Set a review schedule and stick to it |
| Following financial media | Creates urgency and fear that drives poor decisions | Unsubscribe from market news; your IPS is your guide |

## Further Reading

For deeper exploration of the source methodologies:

- **The Little Book of Common Sense Investing** by John Bogle - The case for index investing
- **The Intelligent Investor** by Benjamin Graham - The foundational text on value investing
- **A Random Walk Down Wall Street** by Burton Malkiel - Accessible overview of market efficiency
- **Your Complete Guide to Factor-Based Investing** by Berkin and Swedroe - Factor investing evidence
- **The Bogleheads' Guide to Investing** by Larimore, Lindauer, and LeBoeuf - Practical implementation

The Evidence-Based Portfolio gives you a framework to build an investment philosophy you understand and can maintain for decades, regardless of market conditions.


## Process

1. **Gather information.** Ask the user clarifying questions to understand their specific situation, goals, and constraints
2. **Analyze context.** Review the information provided and identify key factors relevant to investment philosophy builder
3. **Develop recommendations.** Apply domain expertise to create actionable guidance tailored to the user's needs
4. **Present structured output.** Deliver findings in the output format below with clear next steps
5. **Address follow-ups.** Answer additional questions and refine recommendations based on feedback


## Output Format

```template
## Investment Philosophy Builder Analysis

### Assessment
[Key findings and observations]

### Recommendations
1. [Primary recommendation]
2. [Secondary recommendation]
3. [Additional suggestions]

### Action Items
- [ ] [First action step]
- [ ] [Second action step]
- [ ] [Follow-up task]
```


## Edge Cases

- **Incomplete information:** Ask clarifying questions before proceeding with recommendations
- **Conflicting requirements:** Prioritize the most critical constraint and note trade-offs
- **Out of scope requests:** Redirect to appropriate specialized skill or professional resource
- **Beginner vs advanced:** Adjust depth and terminology based on user's experience level


## Example

**Input:** "Help me with investment philosophy builder for my current situation"

**Output:**

Based on your situation, here is a structured approach to investment philosophy builder:

1. **Assessment:** Evaluate your current state and identify key areas for improvement
2. **Strategy:** Develop a targeted plan based on best practices
3. **Implementation:** Execute the plan with specific, measurable steps
4. **Review:** Monitor progress and adjust as needed
