Warren Buffett Stocks: Quality Companies with Durable Moats

Warren Buffett has managed Berkshire Hathaway since 1965, compounding book value at approximately 19.8% annually through 2023 — nearly double the S&P 500's 10.2% over the same period. That performance didn't come from buying the cheapest stocks in the market. It came from identifying businesses so structurally advantaged that their intrinsic value grew faster than most investors expected.

Buffett's framework evolved over two phases. In the 1950s and early 1960s, he followed Benjamin Graham's pure value approach: buy any business trading below its net asset value, hold until the discount closes, sell competitively. This worked until Buffett grew too large and good "cigar butts" became difficult to find. Charlie Munger, his partner since the late 1960s, introduced the key insight that changed everything: a wonderful business at a fair price beats a fair business at a wonderful price over time. The compounding of a franchise accelerates as years pass; a cheap mediocre business stays mediocre.

Today Buffett articulates his criteria with four tests: (1) a business he can understand; (2) favorable long-term economics — meaning a durable competitive advantage; (3) honest, able management; (4) a sensible price. Only criteria 2 and 4 are screenable quantitatively. This screen focuses on criterion 2 (the economic quality test) through ROE consistency, gross margin, FCF generation, and balance sheet conservatism — and uses P/E as a sanity check for criterion 4.

What "wonderful" means in numbers: Buffett has cited 20%+ ROE as a rough threshold for a business with genuine franchise characteristics. He paired this with low debt, because leverage can produce the same ROE number through financial engineering that a moat produces through business quality — and only one of those is sustainable. Gross margin is his unstated but implied test: businesses like Coca-Cola (60%+ gross margin), See's Candies (~60%), Apple (45%+), and Moody's (75%+) earn high returns because customers pay premium prices by choice, not because creditors are subsidizing operations.

Return on Equity (ROE) = Net Income ÷ Shareholders' Equity. It answers the question: for every dollar shareholders have invested, how many cents did management earn? Buffett stated in his 1977 Berkshire letter that the primary test for corporate performance should be return on equity capital, not earnings-per-share growth. EPS grows whenever retained earnings are reinvested — even at mediocre returns. ROE reveals whether that reinvestment is productive.

Why the 5-year average matters more than current ROE:

• Eliminates cyclical peaks: A commodity company might earn 25% ROE when steel or oil prices are elevated, then fall to 6% in a trough. The 5-year average correctly identifies this as a low-quality business.
• Eliminates one-time gains: Asset sales, legal settlements, and insurance recoveries can produce one-year ROE spikes without any change in the underlying business quality.
• Eliminates aggressive buybacks: If a company spends $5B buying back shares, equity shrinks and ROE rises arithmetically. Short-window ROE rewards this; 5-year average smooths it only if the buyback happens at the end of the period.
• Rewards consistency: A company with 18–22% ROE across five different economic conditions — expansion, rate hike, recession, recovery — has demonstrated a structural competitive advantage, not a configuration of luck.

ROE vs. ROIC — which is better? ROE measures returns on equity only. ROIC (Return on Invested Capital) measures returns on all capital deployed — debt plus equity. For companies with debt, ROIC is a more complete picture (and this screen surfaces ROIC at column 7 for cross-reference). Buffett's preference for low-debt businesses actually makes ROE and ROIC converge: at D/E of 0.5 or less, financial leverage does not materially inflate ROE above ROIC. The two columns together, when ROE significantly exceeds ROIC for a debt-light company, signal either a business-quality outlier or an accounting artifact worth investigating.

What sustained high ROE signals: A business consistently earning 20%+ ROE reinvests its retained earnings also at 20%+ — compounding the equity base at a rate that eventually produces spectacular total returns. A company that retained $100M in earnings at 20% ROE over 10 years grew that $100M to $620M in equity base. At the same 20% ROE, this generates $124M in annual earnings on the retained earnings alone — a 24% compounding of the original retained $500M. This is the mathematical engine behind Buffett's wealth creation.

Warren Buffett coined the term "economic moat" — borrowed from medieval castle fortifications — to describe the sustainable competitive advantage that protects a business from competitors. Moats come in five forms: brand power, network effects, switching costs, cost advantages, and regulatory barriers. Gross margin is the quantitative proxy for all five.

Why gross margin measures moat depth: Gross margin = (Revenue − Cost of Goods Sold) / Revenue. It measures how much of every revenue dollar survives after direct production costs. A company with 70% gross margin charges customers $100 for something that costs $30 to produce. That $70 spread exists because customers value the product at $100 and can't replicate it cheaper. When a business can sustain that spread competitively, it signals one or more moats:

• Brand (Coca-Cola, Apple): Customers pay premium prices for the brand identity itself — not just the physical product. Coca-Cola's syrup costs a few cents per can; retail price is ~$1.50. Gross margin ≈ 60%.
• Network effects (Visa, Mastercard): The payment network's value grows with every new user. Merchants accept Visa because cardholders carry it; cardholders carry it because merchants accept it. Transaction fees are largely pure margin once the infrastructure is built.
• Switching costs (Microsoft, Oracle): Enterprises have their workflows, integrations, and employee training embedded in these platforms. Switching costs tens of millions in consulting, retraining, and risk — maintaining a wide gross margin even when competitors offer cheaper alternatives.
• Cost advantages (GEICO within Berkshire): Lowest-cost direct insurance model allows GEICO to price below competitors while maintaining comparable margins.

What low gross margin means: Distributors, retailers, contract manufacturers, and commodity processors typically operate at 10–25% gross margins. These businesses compete on price — any competitor can undercut them if they reduce margin slightly. Sustaining 15%+ ROE in a 15% gross margin business requires exceptional asset turnover and expense discipline — possible, but rare and fragile. A single new competitor, supply chain disruption, or customer consolidation can eliminate the business-quality case. This is why the 30%+ threshold effectively filters for businesses with structural pricing advantages rather than operational efficiency alone.

Buffett's actual holdings as validation: Apple (gross margin ~45%), Coca-Cola (~60%), American Express (~55% service revenue), Moody's (~75%), and Chevron (cyclically lower but infrastructure-advantage driven) all fit this framework. The infamous exception — Kraft Heinz — had gross margin erosion from 38% to 30% between 2015 and 2020, which preceded the $15B goodwill impairment. Buffett publicly acknowledged the Kraft Heinz investment was a mistake; the gross margin compression was an early quantitative signal of moat erosion.

These three frameworks are frequently confused because they all emphasize discipline and fundamentals. They serve different investors with different decision frameworks.

Classic value investing (Graham): Buy any business trading significantly below net asset value or liquidation value. Ben Graham's criteria: P/B under 1.5, P/E under 15, net current asset value above market price ("net-nets"). The philosophy: cheap assets eventually get recognized by the market. Risk: value traps — companies that are cheap because the business is structurally declining and will stay cheap forever. Graham's approach does not require the business to be high-quality; it requires it to be cheap relative to balance sheet assets.

GARP (Growth at a Reasonable Price, Lynch): Buy growing companies trading at a fair price for their growth rate. The PEG ratio (P/E ÷ EPS growth) is the primary tool; PEG ≤ 1.5 is the discipline. GARP requires positive earnings growth and values discipline about what you pay per unit of that growth. GARP investors accept higher P/Es for higher growth rates — a company growing 25% at P/E 37 (PEG 1.5) qualifies. Risk: EPS deceleration causes P/E compression — paying 1.5× PEG for growth that doesn't materialize is costly.

Buffett quality (this screen): Buy businesses with durable competitive advantages, conservative balance sheets, and strong cash generation — at a reasonable (not necessarily cheap) price. Buffett pays P/E 20–30 for franchise businesses he expects to compound at 12–15% annually for decades, rather than paying P/E 8 for a mediocre business earning 6% long-term. The key difference from GARP: Buffett does not primarily use PEG, and he does not require fast growth. A company growing 8% annually with 25% ROE, 60% gross margin, and no debt is a Buffett stock; it may not pass a GARP screen. The investment thesis is enduring return on capital, not current growth rate.

Practical combinations: The three approaches are not mutually exclusive. Companies passing all three frameworks — high sustained ROE, fast EPS growth, low debt, high gross margin, reasonable PEG — are the most powerful compounders. The screens differ primarily in what gets excluded: GARP excludes slow growers regardless of quality; value excludes expensively-priced franchises; Buffett quality excludes fast-growing but capital-intensive businesses regardless of growth rate. This screen's related screens (GARP Stocks and Growth Stocks) provide those alternative lenses on the same universe.

Applying Buffett's qualitative framework through quantitative filters introduces predictable limitations. Understanding them is essential before using this screen to build a real position.

Moats can erode faster than ROE signals update: The 5-year ROE average is a lagging indicator. Blockbuster Video had strong gross margins and high ROE through the mid-2000s while Netflix was destroying its business model. Eastman Kodak maintained 60%+ gross margins on film for decades while digital photography made them irrelevant. The quantitative signal often lags the competitive reality by 2–4 years. Buffett himself acknowledged this problem — his famous quote about newspapers was that they were "franchise businesses" until they weren't, and the transition was hard to time.

Accounting can mask FCF deterioration: Companies can sustain reported earnings while capitalized costs erode FCF. The FCF margin ≥ 10% gate catches acute cases, but gradual erosion — where the FCF margin compresses from 18% to 12% to 8% over 6 years — won't trigger the screen's exclusion criteria until it breaches the floor. Watch the FCF margin column (col 6) for direction, not just current level.

Valuation risk: Buffett explicitly rejects fire-sale pricing — but he also rejects clear overvaluation. This screen uses P/E (col 9) as a sanity check only, not a hard filter. A franchise company with avg ROE of 35%, gross margin of 65%, D/E of 0.1, and FCF margin of 25% may trade at P/E 45 — passing the screen but requiring a long growth runway to justify that P/E. The most famous Buffett overvaluation case is Kraft Heinz, acquired at a premium multiple for what proved to be a slow-growth branded food business losing share to private label. Valuation discipline remains the investor's responsibility, not the screen's.

The "understand the business" criterion can't be screened: Buffett's most commonly cited reason for passing on an investment is that it falls outside his "circle of competence." He famously avoided technology stocks for decades because he didn't understand their moat durability. This screen will surface technology companies with strong quantitative moat signals — it cannot replicate the judgment of whether those moats are structurally durable in 10 years. Apply the results to businesses you understand.

The quantitative screen produces a candidate universe. Converting candidates into a portfolio requires the qualitative judgment Buffett applies to every position — but there are practical frameworks for individual investors.

Entry criteria beyond the screen:

• P/E check: For a company growing 10–12% annually, a fair P/E is roughly 18–22×. For a company growing 15–18%, fair P/E is roughly 22–28×. Paying above 30× requires either faster growth or evidence of continued reinvestment at high ROE into a large addressable market. The P/E column (col 9) surfaces this immediately.
• Gross margin trend: A company with 45% gross margin today that was at 50% five years ago is experiencing moat compression. The current column shows the snapshot — compare to historical filings for direction.
• Management capital allocation: Buffett prizes management that allocates capital consistently to ROE-accretive uses: reinvestment at high returns, selective acquisitions, and buybacks when price is below intrinsic value. Public filings and earnings call analysis (outside this screen) validate this.

Position sizing: Buffett concentrates heavily — Berkshire's top 5 equity positions have historically represented 60–70% of the public equity portfolio. Individual investors managing smaller amounts with less research infrastructure should diversify more: 12–20 positions, each 4–8%, diversified across at least 5 sectors. Above 20 positions the marginal diversification benefit drops sharply while research dilution weakens conviction.

Holding period: The 3-year total return column (col 8) is the right validation window — not quarterly price changes. Buffett's ideal holding period is "forever," meaning the exit trigger is a change in the business (moat erosion, management deterioration, structural disruption) rather than a price target. Rotating into a new position purely because a holding has appreciated is the opposite of the Buffett mindset.

Exit triggers to monitor: Gross margin compresses 300+ basis points for two consecutive annual periods (moat erosion signal). D/E rises above 1.0 (management shifting capital structure). FCF margin drops below 5% for two years (earnings-FCF divergence). 5-year avg ROE falls toward 12% (the moat is no longer producing franchise-level returns). Price rises to P/E above 35–40× without a commensurate re-rating of growth expectations.