Warren Buffett Stock Screening Criteria: The Methodology Behind Moatifi

Warren Buffett's success isn't magic. It's systematic application of business principles that haven't changed in 60 years. The problem is most investors try to copy his stock picks instead of his stock picking process.

I've studied every Buffett shareholder letter, analyzed his major investments, and distilled his approach into specific, measurable criteria. Here's exactly what Buffett looks for and the precise thresholds he uses.

Buffett's Four-Part Test (In His Own Words)

From the 1996 shareholder letter: "Your goal as an investor should be to purchase, at a rational price, a part interest in an easily-understandable business whose earnings are virtually certain to be materially higher five, ten, and twenty years from now."

Translation into screening criteria: 1. Understandable business (Can you explain how it makes money in 30 seconds?) 2. Durable competitive advantage (Economic moat that protects profits) 3. Capable, rational management (Smart capital allocation, conservative leverage) 4. Rational price (Margin of safety)

Let me show you exactly how to screen for each criterion with specific numbers.

Criterion 1: The Economic Moat Test

Buffett's insight: "A truly great business must have an enduring moat that protects excellent returns on invested capital."

ROE: The Moat Detector

Buffett's threshold: ROE consistently above 20% for 5+ years

Why this works: High sustained ROE indicates pricing power. Companies without moats get competed down to average returns (10-15% ROE). Only businesses with genuine competitive protection can maintain 20%+ ROE year after year.

Real examples from our screener: - Apple (AAPL): 164% ROE (ecosystem lock-in creates extreme capital efficiency) - NVIDIA (NVDA): 49% ROE (CUDA software moat generates exceptional returns) - Microsoft (MSFT): 37% ROE (switching costs in enterprise software)

Red flag: Companies with ROE below 15% or highly volatile ROE rarely have strong moats.

ROIC: The Real Profitability Test

Buffett's threshold: ROIC above 15% sustained over 5+ years

Why ROIC matters: ROE can be artificially inflated with debt. ROIC measures returns on all capital (debt + equity), showing true business profitability.

Examples: - NVIDIA: 42% ROIC (confirms the 49% ROE isn't leverage-driven) - Apple: 65% ROIC (extraordinary capital efficiency) - Microsoft: 32% ROIC (software businesses generate returns with minimal capital)

The screening rule: Look for companies where ROIC > cost of capital by at least 10 percentage points. This spread indicates genuine value creation.

What to look for: Gross margins above 40% that are stable or expanding over 5+ years

The logic: Companies with strong moats can maintain or increase gross margins even as competitors try to steal market share. Commodity businesses see margins compress over time.

Real data: - Adobe: Gross margins around 85% (software with minimal marginal costs) - Visa: Gross margins around 97% (network effects create virtually zero marginal costs) - Old Dominion Freight: 30%+ gross margins in trucking (scale advantages in a commodity industry)

Criterion 2: The Management Quality Test

Buffett's famous quote: "When a management with a reputation for brilliance tackles a business with a reputation for bad economics, it is the reputation of the business that remains intact."

Translation: Business quality matters more than management brilliance. But given a great business, management can still destroy value through poor capital allocation.

Debt Level: The Conservative Test

Buffett's rule: Total debt-to-equity below 0.5 for most businesses

Why conservative leverage matters: - Preserves flexibility during downturns - Indicates management doesn't chase growth at any cost - Reduces risk of permanent capital loss

Examples from our screener: - Apple: 0.31 debt-to-equity (conservative despite massive cash flows) - Microsoft: 0.35 debt-to-equity - Texas Pacific Land: 0.0 debt-to-equity (zero debt, maximum financial strength)

Exception: Utilities and regulated businesses can handle higher debt because of predictable cash flows.

What to look for: Flat or declining share count over 5+ years

Why this matters: Share buybacks at reasonable prices create value. Constant dilution (new shares issued) destroys value for existing shareholders.

Positive examples: - Apple: Reduced share count by 35% over the past decade through disciplined buybacks - Microsoft: Modest share reduction while investing heavily in growth

Red flags: - Increasing share count year after year (dilution) - Buybacks at extremely high prices (poor capital allocation)

Free Cash Flow Conversion: The Real Earnings Test

Target: Free cash flow above 80% of reported net income

Why this matters: Companies can manipulate earnings, but cash flow is harder to fake. High conversion rates indicate real, sustainable profits.

Strong examples: - Microsoft: FCF often exceeds net income (working capital benefits) - Visa: Near 100% conversion (asset-light business model) - Adobe: High conversion from subscription revenue model

Criterion 3: The Predictability Test

Buffett's insight: "If you aren't certain that you understand and can evaluate the business, move on."

Revenue Stability: The Visibility Test

Look for: Revenue growth that's consistent, not volatile

Measurement: Calculate revenue standard deviation over 10 years. Lower volatility indicates more predictable business models.

Stable revenue examples: - Paychex: Payroll processing grows steadily with employment and wage inflation - Waste Management: Garbage collection is recession-resistant and location-monopolistic - Procter & Gamble: Consumer staples have predictable demand patterns

Avoid: Highly cyclical businesses where revenue swings 30%+ year-to-year unless you can time cycles perfectly.

Customer Concentration: The Dependency Test

Target: No single customer above 10% of revenue

Why this matters: High customer concentration creates business risk. If one customer leaves, the financial impact can be devastating.

Red flag screening: Companies with 20%+ revenue from single customers are automatically risky regardless of other metrics.

Criterion 4: The Valuation Discipline Test

Buffett's principle: "Price is what you pay; value is what you get."

PE Ratio Reality Check

General rule: PE ratio should not exceed expected growth rate by more than 50%

Example calculation: - Company with 15% expected growth: Maximum reasonable PE around 22-23x - Company with 25% expected growth: PE up to 35-40x might be justified - Mature company with 5% growth: PE above 15x starts looking expensive

Free Cash Flow Yield Test

Target: Free cash flow yield above 5% for mature companies

Calculation: Free cash flow per share divided by stock price Logic: You want decent current returns even before considering growth

Example: - Stock trading at $100 - Free cash flow per share: $6 - FCF yield: 6% (reasonable) - If FCF per share is only $2, yield is 2% (probably overvalued)

The Margin of Safety Rule

Buffett's requirement: Only buy when intrinsic value exceeds price by 25%+ margin

Why margins of safety matter: - Protects against valuation errors - Provides downside protection
- Creates potential for superior returns

Implementation: Calculate what you think the business is worth, then only buy at 75% or less of that value.

How Our Screener Implements These Criteria

Step 1: Quantitative Filtering

Initial screens: - ROE > 20% (5-year average) - ROIC > 15% (5-year average)
- Debt-to-equity < 0.5 - Gross margin > 25% - Positive free cash flow for 5+ consecutive years

This eliminates: ~85% of publicly traded companies

Step 2: Qualitative Moat Analysis

For remaining companies: - Identify specific type of competitive advantage - Assess durability (will moat strengthen or weaken over time?) - Evaluate competitive threats - Assign moat score (1-10)

Step 3: Management Assessment

Key factors: - Capital allocation track record - Communication quality and transparency - Insider ownership and compensation structure - Strategic decision-making history

Step 4: Business Quality Evaluation

Assessment criteria: - Predictability of earnings and cash flows - Simplicity of business model - Industry dynamics and competitive position - Growth runway and reinvestment opportunities

Step 5: Overall Scoring and Risk Analysis

Final output: - Overall score (1-10) synthesizing all factors - Specific investment thesis in plain English - Key risks that could impair the investment case - Recommended position sizing based on conviction level

Real Screening Results: Our Top Buffett-Style Stocks

NVIDIA (9/10 overall): - Moat: CUDA ecosystem creates switching costs + network effects - ROE: 49% (exceptional), ROIC: 42% - Management: 8/10 (strategic vision, conservative balance sheet) - Risk: Valuation is full, custom chips from hyperscalers

Apple (9/10 overall): - Moat: Device ecosystem lock-in + brand power - ROE: 164% (off the charts), ROIC: 65%
- Management: 7/10 (capital allocation excellent, some dependence on China) - Risk: iPhone upgrade cycles slowing, regulatory pressure

Microsoft (9/10 overall): - Moat: Enterprise software switching costs + cloud scale - ROE: 37%, ROIC: 32% - Management: 8/10 (cloud transition executed brilliantly) - Risk: Competition from Google/Amazon in cloud

Common Screening Mistakes

Mistake #1: Focusing Only on Statistical Cheapness

Wrong approach: Buy everything with PE < 10 Buffett's approach: Buy wonderful businesses at fair prices

Why it matters: Cheap stocks are often cheap for good reasons (declining businesses, competitive threats). Better to pay reasonable prices for growing moat companies.

Mistake #2: Ignoring Business Quality

Wrong approach: High ROE = automatic buy Reality check: Cyclical businesses can show high ROE at peak earnings, but results aren't sustainable

Solution: Look for ROE consistency over full business cycles, not just recent peaks.

Mistake #3: Over-Diversification

Buffett's view: "Diversification is protection against ignorance. It makes little sense if you know what you are doing."

Practical application: Better to own 8-12 wonderful businesses you understand deeply than 50 stocks you know superficially.

Mistake #4: Trying to Time Purchases Perfectly

Wrong approach: Wait for the "perfect" price before buying high-quality businesses Better approach: Use dollar-cost averaging into positions over 6-12 months

Why: Market timing is extremely difficult even for great businesses. Gradual accumulation reduces timing risk.

Building Your Buffett-Style Screen

Start Simple

Basic screen criteria: - Market cap > $1 billion (liquidity and stability) - ROE > 20% (5-year average) - Debt-to-equity < 0.5 - Positive earnings for 10+ consecutive years

Add Quality Filters

Second-level criteria: - ROIC > 15% - Gross margin > 40% - Free cash flow positive for 5+ years - Revenue growth positive over 10 years

Manual Qualitative Review

For each remaining stock: - Can you explain the business model in 30 seconds? - What competitive advantages protect this business? - Is management allocating capital rationally? - What could permanently impair this business?

The Bottom Line

Buffett's success comes from systematic application of timeless principles: buy wonderful businesses with durable competitive advantages, run by rational management, at reasonable prices.

The screening criteria aren't complicated, but they require discipline to apply consistently. Most investors fail not because they don't know what to look for, but because they lack the patience to wait for the right opportunities at the right prices.

Key takeaways: - Quality first: Focus on sustainable competitive advantages (high ROE/ROIC) - Conservative management: Low debt, rational capital allocation
- Predictable business models: Avoid complexity and cyclicality when possible - Valuation discipline: Margin of safety protects against errors

Start with these criteria, practice on companies you understand, and gradually develop conviction in businesses that meet Buffett's standards. The goal isn't perfection; it's consistently avoiding big mistakes while participating in the long-term wealth creation of exceptional businesses.

Apply systematic Buffett-style analysis to pre-screened companies using Moatifi's screener - every company scored using the same criteria outlined above.