---
title: "Bull, Base, Bear"
description: "Swoopr Investment teaches scenario analysis for stock investors: how to build bull, base, and bear cases that expose the assumptions your thesis depends on."
canonical: https://www.getswoopr.com/learning-paths/stock-investing/bull-base-bear-scenario-lab/
source: "Swoopr Investment: https://www.getswoopr.com"
---

## Direct Answer



A bull, base, and bear scenario analysis builds three coherent versions of the future for a stock, each with different assumptions about the business and market environment. The purpose is not to predict which will happen but to understand what assumptions drive the investment's value.






      

# Bull, Base, Bear: A Scenario Analysis Lab for Stock Investors



Scenario analysis forces you to confront the assumptions your investment thesis depends on. This lab walks through building three coherent scenarios for a stock and using them to assess whether the potential payoff justifies the position size.






      






## Key Takeaways



- Scenarios are coherent possible worlds, not optimistic, realistic, and pessimistic labels for the same set of assumptions.
- Each scenario specifies the key variables that differ and their plausible range.
- Use only decision-relevant variables in each scenario; adding more variables does not add analytical precision.
- Probability is optional; sensitivity analysis of the key driver is required.
- The scenario gap (the distance between bull and bear outcomes) is the uncertainty you are accepting when you size the position.






## Scenarios are coherent worlds



A scenario is not an emotional label. A bull scenario is not "everything goes right"; it is a specific combination of assumptions about revenue growth, margins, and capital allocation that, together, tell a coherent story about why the business performs better than the market currently expects. A bear scenario is not "everything goes wrong"; it is a specific set of assumptions that hang together logically, such as a revenue miss that triggers margin compression that triggers a balance-sheet constraint.



## Use only decision-relevant variables



Identify the two or three variables that have the largest effect on the stock's estimated value. Build scenarios around those variables alone. Adding a fourth or fifth variable to look thorough makes scenarios harder to communicate and no more accurate. The goal is to understand what drives the outcome, not to model everything.



## Probability is optional; sensitivity is required



You do not need to assign probabilities to scenarios to make them useful. What you do need is to ask: if the bear scenario materializes, how much of my invested capital is at risk? If the answer is uncomfortable, the position may be too large regardless of how likely the bull case seems. Sensitivity to the key driver (what happens if revenue growth is 5% instead of 15%?) is the essential analytical step.






## Applied Exercise: Evidence and Interpretation



Use a company you already follow or a fictional company. Begin by writing the decision question. Then create this two-column note:



| Evidence | Interpretation |
| --- | --- |
| What the primary source reports | What you think it means |
| What changed from the previous period | Why the change may matter |
| What is still unknown | What would resolve the uncertainty |



Add a third column only after the first two are complete: **Decision impact**. Mark each item as *supports*, *weakens*, *neutral*, or *unresolved*. This keeps evidence collection separate from persuasion.








## Frequently Asked Questions


        
### Is this page investment advice?



No. It teaches a research and decision process. The examples are educational and do not recommend any security or allocation.




### Do I need to finish every Swoopr stock page before using this?



No. The learning path intentionally points to deeper reference material only when it becomes relevant to the skill being practiced.




### How do I know when I am ready for the next stage?



Use the stage gate. Progress when you can produce the required artifact without relying on the lesson as a script and can explain both the conclusion and its limitations.




### Should I use a stock screener or AI summary instead of filings?



Those tools can help with discovery and organization, but material facts should be checked against the closest available primary source when practical. A summary is not a substitute for the evidence it summarizes.




### What if the evidence conflicts?



Preserve the disagreement. Do not average conflicting signals into a false sense of certainty. Identify which evidence is more direct, more relevant, and more current, then record what would resolve the conflict.










## References



- [Swoopr Research Methodology and Formulas](https://www.getswoopr.com/research/methodology/)
- [Swoopr: How to Analyze a Stock](https://www.getswoopr.com/stocks/how-to-analyze-a-stock/)
- [Investor.gov: How to Read a 10-K/10-Q](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins/how-read)
- [FINRA: Evaluating Stocks](https://www.finra.org/investors/investing/investment-products/stocks/evaluating-stocks)








## Disclaimer



This page is for educational purposes only and does not constitute investment, financial, or trading advice. Swoopr Investment is not a licensed investment advisor; consult a qualified professional before making investment decisions.












S




By [Swoopr Editorial Team](https://www.getswoopr.com/authors/swoopr-editorial-team/)



The Swoopr Editorial Team researches and writes our technical and fundamental analysis education content, drawing on established market-structure and indicator methodology from primary industry sources. Content is reviewed for accuracy before publication.



Questions or corrections? See our [corrections policy](https://www.getswoopr.com/legal/corrections-policy/) or read more about our [editorial standards](https://www.getswoopr.com/legal/editorial-policy/).