| name | fnd.r-sizing-markets |
| description | Calculates TAM/SAM/SOM and assesses market timing. Use when sizing markets, estimating addressable opportunity, analyzing market timing, or validating opportunity scale. |
| allowed-tools | Read, Write, WebSearch |
| license | Complete terms in LICENSE.txt |
Market Sizing
Calculate market opportunity with TAM/SAM/SOM and timing analysis.
Canvas Files
- Reads: 00.mode.md (VENTURE/BOOTSTRAP affects size requirements)
- Reads: 02.constraints.md (budget, team for SOM calculation)
- Reads: 01.context.md (industry beliefs to validate)
- Writes: 03.opportunity.md
Prerequisites
Before sizing market:
strategy/canvas/00.mode.md must exist (mode affects TAM requirements)
If missing:
"Market sizing requires business mode from 00.mode.md.
VENTURE mode needs TAM >$1B for institutional investors.
BOOTSTRAP mode can target smaller, profitable niches.
Run fnd-architect agent first."
Process
Step 1: Load Context
Read from canvas:
- Mode from 00.mode.md → determines size thresholds
- Constraints from 02.constraints.md → informs SOM calculation
- Beliefs from 01.context.md → hypotheses to validate
Step 2: Calculate TAM (Total Addressable Market)
Use BOTH methods, compare results:
Top-Down Method:
TAM = Industry size from reports × relevant segment %
- Source: Gartner, Forrester, IBISWorld, Statista
- Cite the report and year
Bottom-Up Method:
TAM = Total potential customers × Average revenue per customer
- Count: How many could possibly buy?
- Price: What would they pay annually?
Validation: If methods differ >50%, investigate why.
Step 3: Calculate SAM (Serviceable Addressable Market)
Apply filters to TAM:
SAM = TAM × Geographic filter × Segment filter × Technical filter
| Filter Type | Example | Typical Reduction |
|---|
| Geographic | US only | 30-50% of global |
| Segment | SMB only | 20-40% of total |
| Technical | Cloud-ready | 50-80% of segment |
| Vertical | E-commerce | Varies |
Document each filter with rationale.
Step 4: Calculate SOM (Serviceable Obtainable Market)
Apply realistic capture based on constraints from 02.constraints.md:
SOM = SAM × Realistic market share %
| Timeline | New Entrant | With Traction | Established |
|---|
| Year 1 | 0.5-1% | 1-3% | 3-5% |
| Year 3 | 2-5% | 5-10% | 10-15% |
| Year 5 | 5-10% | 10-20% | 15-25% |
Constraint adjustments:
- Limited budget → lower channel reach → lower SOM
- Small team → slower sales velocity → lower SOM
- Short runway → less time to penetrate → lower SOM
Step 5: Assess Market Timing
Why Now? Framework:
| Factor | Question | Signals |
|---|
| Technology | What's newly possible? | Cost drops, capability jumps |
| Regulation | What's newly required/allowed? | New laws, compliance deadlines |
| Behavior | What habits changed? | Adoption curves, search trends |
| Economics | What's newly affordable? | Price/performance improvements |
| Competition | What gap exists? | Incumbent weakness, market void |
Score each factor 1-5:
Timing Score = Technology + Regulation + Behavior + Economics + Competition
| Score | Interpretation |
|---|
| >20 | Strong timing — move fast |
| 15-20 | Good timing — proceed |
| 10-15 | Questionable — validate further |
| <10 | Poor timing — reconsider |
Step 6: Validate Against Mode
| Mode | TAM Requirement | SAM Requirement |
|---|
| VENTURE | >$1B | >$100M |
| BOOTSTRAP | Any (profitable niche OK) | >$10M |
| HYBRID | >$500M | >$50M |
If below threshold, flag:
"Market size concern for [MODE] mode:
- TAM: $[X] (requirement: $[Y])
Options:
1. Expand market definition
2. Adjacent market expansion
3. Reconsider mode (switch to BOOTSTRAP)"
Step 7: Write Output
Write to strategy/canvas/03.opportunity.md using output format below.
Output Format
# 03. Market Opportunity
## Market Size
| Level | Value | Method | Source |
|-------|-------|--------|--------|
| TAM | $[X]B | [Top-down/Bottom-up] | [Source, Year] |
| SAM | $[X]M | [Filters applied] | [Calculation] |
| SOM (3yr) | $[X]M | [Share %] × SAM | [Assumptions] |
## TAM Calculation
### Top-Down
- Industry: [Name]
- Total size: $[X] ([Source])
- Relevant segment: [X]% = $[X]
### Bottom-Up
- Potential customers: [N]
- Average deal size: $[X]/year
- TAM: [N] × $[X] = $[X]
### Reconciliation
[Explain any difference between methods]
## SAM Derivation
| Filter | Reduction | Remaining |
|--------|-----------|-----------|
| Starting TAM | - | $[X] |
| [Filter 1] | [X]% | $[X] |
| [Filter 2] | [X]% | $[X] |
| **SAM** | - | **$[X]** |
## SOM Assumptions
- Year 1 share: [X]% = $[X]
- Year 3 share: [X]% = $[X]
- Rationale: [Why these shares are achievable]
## Why Now
| Factor | Score | Evidence |
|--------|-------|----------|
| Technology | [1-5] | [What's newly possible] |
| Regulation | [1-5] | [What's changed] |
| Behavior | [1-5] | [What shifted] |
| Economics | [1-5] | [What's affordable] |
| Competition | [1-5] | [What gap exists] |
| **Total** | **[X]/25** | |
## Market Trends
### Tailwinds
- [Trend 1]: [Impact on opportunity]
- [Trend 2]: [Impact on opportunity]
### Headwinds
- [Trend 1]: [Mitigation strategy]
- [Trend 2]: [Mitigation strategy]
## Market Risks
| Risk | Probability | Impact | Mitigation |
|------|-------------|--------|------------|
| [Risk 1] | H/M/L | H/M/L | [Strategy] |
| [Risk 2] | H/M/L | H/M/L | [Strategy] |
## Mode Validation
**Mode:** [From 00.mode.md]
[Met/Not Met]
[Proceed/Expand/Reconsider]
Quality Criteria
Before finalizing, verify:
Boundaries
- Does NOT validate customer demand (see fnd.r-scoring-problems)
- Does NOT guarantee market capture
- Does NOT predict competitor response
- Market size is estimate, not fact — cite sources
- SOM is constrained projection, not target
- Timing assessment is point-in-time, markets change
- Does NOT handle multi-market or platform economics
