Modeling Bull, Bear, and Base Cases
The difference between amateur and professional valuation is often not the formula used, but the depth of thought applied to each scenario. A casual investor writes "base case = $50" without explaining the journey. A skilled analyst builds a scenario with documented assumptions, articulate reasoning, and explicit trade-offs between growth, margins, and risk. This chapter teaches you how to construct scenarios that are defensible, internally consistent, and grounded in real business understanding rather than numerical fantasy.
Quick Definition
A scenario in valuation is a coherent narrative about how a business might evolve over time, expressed through integrated assumptions about revenue growth, operating margins, capital efficiency, and risk. The bear case is a legitimate-but-pessimistic outcome. The base case is your most honest estimate. The bull case is an optimistic-but-plausible future. Each scenario should tell a story where assumptions reinforce one another and reflect real competitive or operational dynamics, not random numerical variation.
Key Takeaways
- Each scenario is a narrative where growth, margins, risk, and capital intensity move together in ways that reflect real business dynamics.
- The bear case is not bankruptcy or catastrophe; it's a "significant disappointment" scenario where the company remains viable but underperforms.
- The base case is where you place your honest conviction, not artificially conservative assumptions designed to avoid accusations of optimism bias.
- The bull case requires identified catalysts—new products, market expansion, competitive wins, operational leverage—not wishful thinking or "if everything goes right."
- Discount rates should vary across scenarios: higher in bear cases (more risk), lower in bull cases (less risk as execution de-risks).
- A scenario is only as strong as the weakest assumption; audit your frameworks for internal contradictions.
- Real scenario analysis requires building full DCF models for each case, not simplified estimates or rules of thumb.
Building the Bear Case: Defensive Thinking
The bear case is difficult for many investors because it requires imagining failure or significant disappointment. Yet this is precisely why it's valuable—the bear case forces you to identify real downside risks you might otherwise ignore.
The Bear Case Narrative
A strong bear case starts with a plausible trigger event or condition. Ask yourself:
What would have to happen for this investment to disappoint significantly?
For a software company, the bear case might trigger from:
- A well-funded competitor enters with aggressive pricing
- The company loses a major customer or vertical
- Adoption slows due to product limitations or market saturation
- Macro slowdown reduces customer spending and stretches sales cycles
For an industrial company, bear case triggers might include:
- Industry capacity oversupply drives pricing pressure
- A key customer consolidates suppliers, leaving the company as second-tier vendor
- Input costs rise (commodities, labor, energy) faster than pricing can recover
- Macro recession reduces industrial spending
For a retailer, bear case triggers include:
- E-commerce competition intensifies margins
- Supply chain costs remain elevated
- Consumer spending slows, forcing promotions and margin surrender
Once you've identified a plausible trigger, build the assumption chain:
Example: SaaS Company Bear Case
Trigger: A well-funded competitor (funded by a FAANG or large PE firm) enters the market with free or low-cost offerings to grab market share.
Consequence chain:
- The competitor captures 10–15% of the addressable market within 18–24 months
- The company must respond with discounts and increased customer acquisition spending to compete
- Revenue growth slows from 18% to 8–10% (losing market share AND facing longer sales cycles)
- Customer acquisition cost (CAC) rises 30–40% due to increased competition for attention
- Net dollar retention declines from 110% to 100% (existing customers churn faster due to competitive alternatives)
- Operating margin contracts 400–600 basis points (lower revenue growth + higher CAC + churn prevention spending)
Narrative closure: The company survives but becomes a smaller, slower-growth, lower-margin business. It remains profitable but is no longer a high-growth compounder. It becomes an acquisition target or stagnates as a mid-market player.
Bear Case Assumptions
| Metric | Bear Case |
|---|---|
| Revenue growth (years 1–5) | 8% |
| Revenue growth (terminal) | 2% |
| EBITDA margin (years 1–5) | 25% (declining from current 32%) |
| Terminal EBITDA margin | 22% |
| Discount rate (WACC) | 11% (higher than base 10%) |
| Terminal growth rate | 2% (mature, low-growth outcome) |
| Tax rate | 25% |
| CapEx as % of revenue | 5% |
| Working capital change | Neutral to slightly negative (cash strains from growth slowdown) |
Narrative consistency check: Does 8% growth with declining margins make sense for this company facing competitive pressure? Yes—market share losses and competitive response both pressure growth and margins. Does 11% discount rate (higher than base) reflect elevated risk? Yes—execution risk and competitive dynamics are heightened.
Grounding Bear Case in Reality
The strongest bear cases are those corroborated by real market commentary. Ask:
- Have short-sellers articulated this thesis?
- Do analyst reports mention these risks?
- Has management acknowledged these challenges in earnings calls?
- Are credible investors voicing these concerns?
If your bear case is unique to you and no one else in the market articulates similar concerns, double-check your logic. Either you've identified a hidden risk (possible but rare) or you're being unreasonably pessimistic (more common).
Building the Base Case: Honest Conviction
The base case is the scenario where you put your genuine belief. This is not where you build in artificial conservatism or hedging. It's where you say, "Based on my research, here's what I think will actually happen."
Many investors make the mistake of treating base case as a defensive position—padding assumptions to be safe. Instead, base case should be your most likely outcome after genuine analysis.
Base Case Narrative
The base case narrative reflects steady-state execution and market dynamics. For most businesses, base case assumes:
- Management executes the stated strategy reasonably well but not flawlessly
- Competitive dynamics remain similar to current conditions (no major disruptions)
- Macro environment is neutral to slightly positive
- The company achieves its own guidance or analyst consensus expectations
- Operational leverage develops as expected, but no surprises
- Capital allocation is competent, not exceptional
Example: SaaS Company Base Case
Narrative: The company continues executing its product roadmap, maintaining differentiation against existing and new competitors. Customer retention remains strong (net dollar retention 105–110%). The company grows in-line with market growth (~12–15%). Operating leverage develops as the company scales—existing costs are spread across larger revenue base. Margins expand modestly. The company becomes an established mid-market SaaS player with stable growth characteristics.
Base Case Assumptions
| Metric | Base Case |
|---|---|
| Revenue growth (years 1–5) | 12% |
| Revenue growth (terminal) | 3% |
| EBITDA margin (years 1–5) | 32% (stable) |
| Terminal EBITDA margin | 33% |
| Discount rate (WACC) | 10% |
| Terminal growth rate | 3% |
| Tax rate | 25% |
| CapEx as % of revenue | 4% |
| Working capital change | Neutral (growing proportionally with revenue) |
Rationale: 12% revenue growth reflects the company's historical 3-year growth average and market TAM expansion. 32% EBITDA margin is current state; the company maintains this through balance of pricing discipline and cost control. 10% discount rate is standard for a mid-cap SaaS company with moderate execution risk. Terminal growth of 3% is slightly above GDP growth, reflecting durable but not exceptional market position.
The Difference Between Base Case and Analyst Consensus
Don't confuse base case with analyst consensus. Your base case should reflect your own analysis, even if it differs from consensus. However, if your base case is dramatically different from consensus, ask yourself: have 20 professional analysts all missed something you've identified? Or are you overconfident? This isn't to say you should copy consensus—just to use it as a calibration check.
Building the Bull Case: Plausible Upside
The bull case is often where investors go wrong. They drift from "plausible" into "wish fulfillment." A strong bull case has catalysts you can name, not vague optimism.
Bull Case Narrative with Identified Catalysts
The strongest bull cases are built around specific, achievable catalysts. These might include:
Product catalysts: A new product or major feature release addresses an adjacent market, expanding TAM. Example: A CRM company launches a marketing automation module, doubling addressable market.
Market catalysts: Industry consolidation, regulatory changes, or adoption shifts expand the opportunity. Example: A shift toward cloud adoption accelerates company's growth trajectory.
Geographic catalysts: International expansion or emergence in new regions provides a second or third growth engine. Example: A US software company enters European market with strong local sales team.
Operational catalysts: Automation, manufacturing efficiency, or margin improvement through scale. Example: A hardware company achieves gross margin expansion from manufacturing optimization.
Acquisition/merger catalysts: Strategic M&A adds capabilities, market share, or revenue. Example: The company acquires a competitor and achieves cross-sell synergies.
Market shift catalysts: The company is positioned to benefit from secular tailwinds. Example: As enterprises prioritize cybersecurity, the company's security-focused product gains market share.
Example: SaaS Company Bull Case
Primary catalyst: The company's product gains traction in an adjacent vertical (e.g., healthcare, where regulatory compliance creates higher switching costs and pricing power).
Secondary catalysts:
- Customer lifetime value (LTV) increases from higher pricing and longer retention in regulated verticals
- Net dollar retention improves to 115% from existing customers and cross-sell of complementary products
- International expansion (initially UK/Canada, later EU) provides second growth engine
- Operating leverage expands margins as the company achieves scale and R&D becomes less of a cost bottleneck
Narrative closure: The company evolves from a mid-market horizontal player to a high-growth vertical-specific platform. Pricing power increases. Margins expand. Growth accelerates. The company becomes an acquisition target for a large enterprise software vendor or scales to IPO.
Bull Case Assumptions
| Metric | Bull Case |
|---|---|
| Revenue growth (years 1–5) | 18% |
| Revenue growth (terminal) | 4% |
| EBITDA margin (years 1–5) | 36% (expanding from operational leverage and pricing power) |
| Terminal EBITDA margin | 38% |
| Discount rate (WACC) | 9% (lower than base due to de-risking) |
| Terminal growth rate | 4% (stronger market position) |
| Tax rate | 25% |
| CapEx as % of revenue | 3% (revenue growing faster, CapEx intensity declining) |
| Working capital change | Modest positive cash flow from scale and improved collections |
Rationale: 18% growth reflects successful vertical expansion and international rollout. 36% margin reflects operating leverage (R&D spread across larger base) and pricing power in new verticals. 9% discount rate reflects lower risk as business de-risks through scale and diversification. 4% terminal growth reflects the company's enhanced market position and sustained competitive advantages.
Catalyst test: Is this plausible? The SaaS company has proven product-market fit. Vertical expansion is standard playbook (e.g., Salesforce extended from CRM to Service Cloud). International expansion in SaaS is common and proven. Are margins realistic? For SaaS at scale, 36% EBITDA margin is ambitious but achievable (Atlassian, Adobe, Workday all achieved this). The bull case passes the plausibility test.
Scenario Comparison Table
When all three scenarios are built, organize them in a comparison table:
| Metric | Bear | Base | Bull | Unit |
|---|---|---|---|---|
| Growth & Scale | ||||
| Year 1-5 revenue CAGR | 8% | 12% | 18% | % |
| Year 1 revenue | $100M | $100M | $100M | $ millions |
| Year 5 revenue | $147M | $176M | $229M | $ millions |
| Terminal revenue growth | 2% | 3% | 4% | % |
| Profitability | ||||
| Year 1-5 EBITDA margin avg | 25% | 32% | 36% | % |
| Terminal EBITDA margin | 22% | 33% | 38% | % |
| Risk & Cost of Capital | ||||
| Discount rate (WACC) | 11% | 10% | 9% | % |
| Terminal growth rate | 2% | 3% | 4% | % |
| Valuation Output | ||||
| Enterprise value | $400M | $800M | $1,200M | $ |
| Equity value (after debt) | $350M | $750M | $1,150M | $ |
| Per-share value (10M shares) | $35 | $75 | $115 | $ |
| vs. current price ($60) | -42% | +25% | +92% | % |
This table discipline forces you to ensure scenarios are truly differentiated. If bear case is only 20% different from base, you haven't built real scenarios.
Ensuring Internal Consistency
A common mistake is scenarios where assumptions conflict. Check:
Growth and Margin Alignment:
- In recession (bear), does revenue growth slow AND margins compress? Yes, both should move down together.
- In expansion (bull), does growth accelerate AND margins expand? Yes, both should improve together.
- This isn't accidental—they're causally linked in real businesses.
Risk and Discount Rate Alignment:
- Bear case has higher risk (execution pressure, competition)? Discount rate should be higher.
- Bull case has lower risk (execution proven, scale achieved)? Discount rate should be lower.
- Base case has moderate risk? Discount rate should be moderate.
Capital Intensity and Growth:
- Fast-growth case (bull) might have higher CapEx intensity initially (infrastructure investment).
- Or lower CapEx intensity (SaaS, capital-light model).
- Be explicit about why capital intensity varies.
Working Capital and Growth:
- Growing revenue typically requires working capital investment (receivables, inventory).
- Unless you have a specific reason (improving collections, inventory efficiency), working capital should grow with revenue.
- If bear case has slowing growth, working capital should release less cash.
Real-World Scenario Examples
Example 1: AI Infrastructure Company
Bear Case (15% probability):
- Market growth slows to 25% (from 30%+) as AI adoption plateaus
- Pricing pressure from competition; gross margin declines from 68% to 62%
- Discount rate: 12%
- Per-share value: $40
- Narrative: Rapid AI adoption creates crowded market; the company faces pricing pressure and growth deceleration
Base Case (60% probability):
- Market growth 28%; company captures market share
- Gross margin: 66%; operating leverage improves EBITDA margin to 30%
- Discount rate: 10%
- Per-share value: $95
- Narrative: The company executes well; AI adoption accelerates but market remains robust
Bull Case (25% probability):
- Market growth 35%; the company wins disproportionate share through superior engineering
- Gross margin: 70% (pricing power); EBITDA margin: 35%
- Discount rate: 8%
- Per-share value: $155
- Narrative: The company becomes the de facto standard; network effects and switching costs drive market share gains
Expected value: (40 × 0.15) + (95 × 0.60) + (155 × 0.25) = $100
Market price: $80. Upside: 25%.
Example 2: Mature Industrial Manufacturer
Bear Case (20% probability):
- Tariffs increase input costs; unable to pass through pricing
- Revenue growth: 0% (flat); margin compression from 16% to 12%
- Discount rate: 12%
- Per-share value: $22
- Narrative: Protectionist environment; the company struggles with cost management
Base Case (55% probability):
- Steady market; automation investments improve margins
- Revenue growth: 3%; margin improvement to 16.5%
- Discount rate: 10%
- Per-share value: $48
- Narrative: The company executes automation roadmap; margins stable with modest operating leverage
Bull Case (25% probability):
- Wins major new contract; captures market share from weaker competitor
- Revenue growth: 6%; margin expansion to 18% from scale and pricing
- Discount rate: 9%
- Per-share value: $72
- Narrative: Consolidation in industry; the company is an acquirer or wins significant new business
Expected value: (22 × 0.20) + (48 × 0.55) + (72 × 0.25) = $49
Market price: $45. Upside: 9%. Risk/reward is balanced but not compelling; modest margin of safety.
Scenario Modeling Framework Visualization
Common Mistakes
1. Bear case assumes bankruptcy or extreme disruption. Bear case should be "significant disappointment," not "company destroyed." If bear case assumes $5 valuation and you're weighing it 20%, you're over-hedging. Tighten the range.
2. Base case is too conservative. Investors often build base case with hidden conservatism ("I'll use 10% growth instead of my honest 12% to be safe"). This creates a false sense of security. Base case should be your honest conviction.
3. Bull case lacks catalysts or is generic ("everything goes right"). The bull case is only credible if you can name specific catalysts. "Product launch," "geographic expansion," "margin improvement from automation"—not "the company executes exceptionally."
4. Discount rates are identical across scenarios. Risk clearly differs between scenarios. Bear case should have higher discount rate (more risk). Bull case should have lower rate (less risk as execution de-risks).
5. Assumptions contradict each other. Growth and margins should move together logically. If you assume fast growth (bull) but declining margins, explain why. Otherwise, it's an inconsistent scenario.
6. Margins or growth assumptions are unrealistic. Check historical precedent and peer comparison. If your bull case assumes 50% margins for a company whose peers max out at 40%, you're being unrealistic (unless you have a specific reason for premium).
7. No narrative justification for numbers. Each assumption should be defensible with a specific reason. "EBITDA margin 36% because of operating leverage and pricing power in new verticals" is good. "36% to be optimistic" is not.
FAQ
Q: Should bull case margins always be higher than base case?
Usually yes, because scale and successful execution bring operating leverage. But not always. A company entering a new, highly competitive market might have higher growth but temporarily lower margins as it invests to gain traction. Be explicit about the mechanics.
Q: What if I have four scenarios instead of three?
You can model four (or more), but three is standard. If you have four, consider whether two of them can be merged or whether one can be eliminated. If all four are genuinely plausible and materially different, keep them, but the added complexity may not be worth the marginal insight.
Q: How do I choose between scenarios when building my base case?
Your base case should reflect your most likely outcome, not the average of other scenarios. If you're 60% confident in one scenario and 40% in another, base case is the 60% scenario, not a 50/50 blend.
Q: Should I present all three scenarios to management?
Carefully. A bear case report to the company's CFO may be seen as pessimistic or confrontational. A research report or investor memo with balanced scenarios is standard. Context matters.
Q: How do I know if my scenarios are too wide or too narrow?
A good range is 3–4x from bear to bull (e.g., $25 to $75, a 3x range). If range is 10x, scenarios are probably too extreme. If range is 1.2x, scenarios aren't differentiated enough. 3–4x is normal for real businesses.
Q: Can I use different explicit forecast periods for different scenarios?
Yes. Bear case might stabilize faster (5-year explicit period, terminal after). Bull case might take longer to reach steady-state (10-year explicit period). Different explicit periods are fine if justified by the narrative.
Related Concepts
- How to Assign Probabilities — Methodology for setting probability weights that reflect conviction and historical outcomes.
- Expected Value in Valuation — The calculation and interpretation of probability-weighted expected values.
- Building a Simple DCF Model — Foundational DCF techniques applied to each scenario.
- Sensitivity Analysis in DCF — How sensitivity analysis complements scenario analysis.
Summary
Building bull, bear, and base cases is where valuation transitions from mechanical formula-application to genuine business analysis. Each scenario is a narrative—a story about how the business might evolve, told through integrated assumptions about growth, profitability, risk, and capital efficiency. The bear case forces you to articulate real downside risks. The base case is where you place honest conviction. The bull case requires you to name specific catalysts, not just express optimism. When all three are built with internal consistency and defensible assumptions, they form the foundation of a rigorous valuation framework. The discipline of scenario building—creating three distinct narratives, validating assumptions against historical precedent, and ensuring logical coherence—is what separates serious valuation work from numerical wishful thinking.
Next
Continue to How to Assign Probabilities to learn how to set probability distributions that reflect genuine conviction and improve decision-making.