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Value Investing Mastery: Warren Buffett & Benjamin Graham Principles

September 3, 2025
13 min read

The Philosophy of Value Investing

Value investing is the discipline of buying securities trading below their intrinsic value. Pioneered by Benjamin Graham in the 1930s and refined by Warren Buffett, this approach has produced more billionaire investors than any other strategy.

The core insight is simple: the stock market is a voting machine in the short term (driven by emotion) but a weighing machine in the long term (driven by fundamentals). Value investors exploit this disconnect—buying when fear creates bargains and selling when greed creates overvaluation.

Buffett's Core Principle

"Price is what you pay. Value is what you get." A great company at the wrong price is a bad investment. A mediocre company at a great price can be a good investment. The relationship between price and value is everything.

Intrinsic Value: The Math Behind Value Investing

Intrinsic value is what a business is actually worth based on its future cash flows. Every valuation method attempts to answer: "How much cash will this business generate, and what is that cash worth today?"

Method 1: Discounted Cash Flow (DCF)

The gold standard for intrinsic value calculation.

Intrinsic Value = Σ (Future Cash Flow / (1 + Discount Rate)^Year)

Inputs Required:

  • • Free Cash Flow (FCF) projections
  • • Growth rate assumptions
  • • Discount rate (usually 10-15%)
  • • Terminal value estimate

Practical Example:

Company generates $100M FCF growing 10%/year for 10 years, then 3% perpetually. At 10% discount rate:

Intrinsic Value ≈ $2.1 Billion

Method 2: Earnings Power Value (EPV)

Graham's preferred method—simpler and more conservative.

EPV = Adjusted Earnings / Cost of Capital

Steps:

  1. Start with operating earnings (EBIT)
  2. Adjust for one-time items and cyclical factors
  3. Apply sustainable tax rate
  4. Divide by cost of capital (8-12% typical)
  5. Add excess cash, subtract debt

Example: $50M normalized earnings / 10% = $500M EPV

Method 3: Asset-Based Valuation

For asset-heavy or distressed companies.

Net-Net (Graham's Cigar Butt)

Current Assets - Total Liabilities

Buy below this = getting business for free

Tangible Book Value

Total Assets - Intangibles - Liabilities

Floor value if company liquidated

Margin of Safety: The Most Important Concept

The margin of safety is the buffer between price paid and estimated intrinsic value. It's your protection against analytical errors, unexpected events, and the inherent uncertainty of business forecasting.

Graham's Rule

Never pay more than 2/3 of intrinsic value. If your analysis says a stock is worth $90, don't pay more than $60. This 33% margin covers your mistakes.

No Margin (0%)

Buying at fair value. Any negative surprise = loss.

Risk: Very High

Moderate (25%)

Some cushion but limited protection.

Risk: Moderate

Graham Standard (33%+)

Significant protection. Room for error.

Risk: Lower

Finding Value: Screening Criteria

Value stocks don't announce themselves. You need systematic screening to find candidates, then deep research to separate genuine value from value traps.

Graham's Classic Criteria

  • P/E ratio < 15 (or < 40% of prior 5-year high P/E)
  • P/B ratio < 1.5 (or P/E × P/B < 22.5)
  • Current ratio > 2.0 (strong liquidity)
  • Debt-to-equity < 0.5
  • 10+ years of positive earnings
  • Dividend paid for 20+ years

Modern Buffett Additions

  • ROE consistently > 15%
  • ROIC > WACC (creates value)
  • Free cash flow positive and growing
  • Durable competitive advantage (moat)
  • Management with skin in the game
  • Business you can understand

Economic Moats: Buffett's Edge

Buffett evolved beyond Graham by focusing on quality businesses with durable competitive advantages—economic moats that protect profits from competition.

Brand Power

Pricing power from reputation. Coca-Cola charges premium for sugar water.

Test: Can they raise prices without losing customers?

Network Effects

Value increases with users. Visa, Mastercard, social networks.

Test: Do users attract more users?

Switching Costs

Pain of switching providers. Enterprise software, banks.

Test: Would customers pay to avoid switching?

Cost Advantages

Structural cost leadership. Scale, location, process advantages.

Test: Can competitors match their costs?

Buffett's Test: "If you gave me $10 billion and told me to go compete with [company], could I take significant market share?" If the answer is no, there's probably a moat.

Value Traps: What to Avoid

A value trap is a stock that looks cheap but deserves to be cheap— and often gets cheaper. Learning to distinguish value from traps is the hardest part of value investing.

Secular Decline

Industry being disrupted (newspapers, traditional retail). Low P/E reflects permanently impaired future earnings, not opportunity.

Cyclical Peak

Commodity/cyclical companies look cheapest at peak earnings. The low P/E precedes an earnings collapse. Use normalized earnings instead.

Financial Engineering

Earnings boosted by buybacks, accounting changes, or one-time items. Always analyze free cash flow, not just reported earnings.

Hidden Leverage

Operating leases, pension liabilities, off-balance-sheet debt. The balance sheet looks clean but obligations are hidden.

Practical Value Investing Process

1

Screen

Use quantitative filters (P/E, P/B, debt ratios) to generate candidate list

2

Understand the Business

Read 10-Ks, understand the industry, identify competitive position

3

Assess the Moat

Is there durable competitive advantage? What protects margins?

4

Calculate Intrinsic Value

Use multiple methods (DCF, EPV, comparables) and triangulate

5

Demand Margin of Safety

Only buy at 30%+ discount to your conservative estimate

6

Wait

Value investing requires patience. The market may take years to recognize value.

Key Takeaways

1

Price and value are different—successful investing requires knowing both

2

Margin of safety is non-negotiable—never pay fair value or above

3

Quality matters—a great business at a fair price beats a fair business at a great price

4

Avoid value traps—cheap can always get cheaper if fundamentals deteriorate

5

Patience is the value investor's edge—most people can't wait, and that's your opportunity