Three Reasons to Sell - AI Analysis Prompt
Use this Philip Fisher rule prompt to apply “Three Reasons to Sell” to a specific company. It turns a vague opinion into a repeatable checklist: what facts you must verify, which assumptions matter most, what would invalidate the thesis, and the common misreads that create false certainty. Expect a written output you can save: a thesis summary, key risks, and next-step questions for filings and earnings calls. If a claim matters, require primary-source citations before you act. Educational only — not investment advice.
Full Prompt
You are an investment analyst trained in Philip Fisher's principle of "Three Reasons to Sell." Your core philosophy: growth investing, scuttlebutt method, management quality. Your task is to analyze {Company Name} through the specific lens of this principle.
## Context
Philip Fisher teaches: "Sell only when: 1) You made a mistake in original analysis, 2) The company no longer meets the fifteen points, or 3) A clearly better opportunity exists."
## Analysis Framework
### 1. Principle Application Assessment
- How does this principle specifically apply to {Company Name}?
- What aspects of the company are most relevant to "Three Reasons to Sell"?
- Rate the company's alignment with this principle: Strong / Moderate / Weak
- What would Philip Fisher focus on first when evaluating this company?
### 2. Quantitative Evidence
- Identify 3-5 key financial metrics most relevant to this principle
- Analyze these metrics over the past 5-10 years for {Company Name}
- Compare with industry peers and historical benchmarks
- Are the numbers improving, stable, or deteriorating?
- What story do the numbers tell through the lens of "Three Reasons to Sell"?
### 3. Qualitative Deep Dive
- Evaluate the non-quantifiable factors Philip Fisher would examine
- Management quality and alignment with this principle
- Industry dynamics and competitive position
- Business model sustainability viewed through this specific lens
- What would Philip Fisher want to know that isn't in the financial statements?
### 4. Risk Assessment Through This Lens
- What risks does this principle specifically highlight for {Company Name}?
- What could go wrong that this principle is designed to protect against?
- Are there warning signs that Philip Fisher would flag?
- Stress-test: How would this company perform under adverse conditions?
- What is the worst-case scenario from this principle's perspective?
### 5. Opportunity Identification
- What opportunities does analyzing through this lens reveal?
- Are there hidden strengths the market may be undervaluing?
- How does this company compare to Philip Fisher's ideal investment?
- What catalysts could unlock value related to this principle?
### 6. Fisher Verdict
- Summarize: Does {Company Name} pass the "Three Reasons to Sell" test?
- Rate the investment opportunity: 1-10 from this principle's perspective
- Clear recommendation: Buy / Hold / Avoid (based on this principle alone)
- What conditions would change your assessment?
- One-paragraph summary capturing Philip Fisher's likely assessment
## Output Format
Present your analysis with specific data points in each section. Use Philip Fisher's analytical style: deep qualitative research focusing on growth potential and management excellence. End with a decisive verdict.Related reading (close the loop)
Pick one path below to turn the output into a checkable, repeatable decision policy.
- Read the matching principleDefinition, boundaries, pitfalls, and a minimal checklist.
- Master profileMethodology summary + common misreads for this framework.
- Practice in scenariosTranslate conclusions into “what I do under stress”.
- More prompts from this masterTriangulate with multiple rules instead of anchoring on one prompt.
Educational only. Verify facts with primary sources and apply your own constraints.
Basic Questions
When does Fisher think you should sell a stock?
Fisher's selling criteria are very strict — he believed frequent selling means wrong buying:
🔴 Fisher's three reasons to sell:
1. Original judgment was wrong: Deeper research reveals the company isn't as good as thought
2. Company no longer qualifies: Management deterioration, competitive advantage lost, market saturated
3. Found clearly better opportunity: But this should be extremely rare
🟢 Should NOT sell:
- Just because stock dropped short-term
- Just because overall market declined
- Just because it's up a lot and you want to 'lock in profits'
Fisher held Motorola and similar companies for over 20 years.
🔴 Fisher's three reasons to sell:
1. Original judgment was wrong: Deeper research reveals the company isn't as good as thought
2. Company no longer qualifies: Management deterioration, competitive advantage lost, market saturated
3. Found clearly better opportunity: But this should be extremely rare
🟢 Should NOT sell:
- Just because stock dropped short-term
- Just because overall market declined
- Just because it's up a lot and you want to 'lock in profits'
Fisher held Motorola and similar companies for over 20 years.
Usage Tips
Is the AI's 1-10 rating reliable?
⚠️ Sell assessment isn't a simple yes/no — it's an ongoing dynamic judgment.
The rating's unique value:
- Fisher would sell only in three situations: the original buy thesis was wrong, the company no longer meets standards, or a clearly better opportunity is found
- The score helps distinguish "genuine sell signals" from "short-term noise" — price drops aren't sell reasons; fundamental deterioration is
- Most valuable is comparing the current state against your original buy reasons one by one — if core reasons still hold, don't sell
Core reminders:
- Fisher believed the biggest selling mistake is "selling excellent companies too early" — far more common and fatal than selling too late
- AI may over-recommend selling due to short-term negative news; apply your long-term perspective as correction
- Don't sell just because you've made a lot — "I've profited enough" is not a sell reason Fisher would endorse
The rating's unique value:
- Fisher would sell only in three situations: the original buy thesis was wrong, the company no longer meets standards, or a clearly better opportunity is found
- The score helps distinguish "genuine sell signals" from "short-term noise" — price drops aren't sell reasons; fundamental deterioration is
- Most valuable is comparing the current state against your original buy reasons one by one — if core reasons still hold, don't sell
Core reminders:
- Fisher believed the biggest selling mistake is "selling excellent companies too early" — far more common and fatal than selling too late
- AI may over-recommend selling due to short-term negative news; apply your long-term perspective as correction
- Don't sell just because you've made a lot — "I've profited enough" is not a sell reason Fisher would endorse
Getting started
Does this prompt give investment advice or buy/sell calls?
No. It is a research helper that turns your thinking into checkable inputs and constraints: what evidence you must verify, what would prove the thesis wrong, and what common misreads to avoid. Treat the output as a draft, not a signal. Validate every material number against primary sources (filings, earnings releases, investor presentations, transcripts), and do not act unless you can write down (1) position-size limits and (2) explicit invalidation triggers.
What inputs should I provide for a reliable result?
At minimum: a 1-sentence business model summary, your current thesis (why it wins/loses), time horizon, and risk constraints; a valuation/price range; and the latest financial statements (profit quality, cash flow, debt/liquidity). Add context that reduces hallucinations: the exact filing period, known one-offs, key competitors, and what you do NOT know yet. If an input is missing, label it as missing evidence instead of letting the model guess.
Validation and boundaries
How do I validate the output?
Validate falsifiable claims one by one. Rewrite each key statement into something you can check: the metric, the period, and the source. Numbers must match filings; management claims must be traceable to transcripts/guidance; and “moat” claims need observable evidence (pricing power, retention, switching costs, cost structure). Anything you cannot verify becomes a follow-up task, not a decision trigger. If the model cites dates, confirm they are not beyond its knowledge cutoff.
When should I NOT act on the output?
If you cannot write down invalidation triggers, a position-size cap, or primary-source evidence for the key claims behind “Three Reasons to Sell”, do not act. The safer move is usually to reduce size, slow down, and schedule the next review.
More Rule Prompts
Explore other investment principles from this master.
Few Outstanding Investments
I don't want a lot of good investments; I want a few outstanding ones. Concentration in your best ideas is key.
→Hold Forever
If the job has been correctly done when a common stock is purchased, the time to sell it is almost never.
→Management Integrity
Does the management have unquestionable integrity? Management that misleads shareholders will eventually mislead investors.
→Worthwhile Profit Margins
Does the company have a worthwhile profit margin? Growth without profit is meaningless.
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