| name | market-sizing |
| compatibility | Claude Code 2.1.220+ |
| description | TAM/SAM/SOM market sizing with top-down and bottom-up estimation methods, cross-validation of assumptions, and divergence reconciliation. Generates investor-ready materials with growth projections and confidence intervals. Use when estimating addressable markets, validating opportunity size, or preparing pitch deck market slides. |
| version | 1.0.0 |
| author | OrchestKit |
| user-invocable | false |
| disable-model-invocation | false |
| complexity | medium |
| persuasion-type | guidance |
| tags | ["tam","sam","som","market-size","addressable-market","opportunity-sizing"] |
| context | fork |
| agent | product-strategist |
| metadata | {"category":"document-asset-creation"} |
| allowed-tools | ["Read","Glob","Grep","WebFetch","WebSearch"] |
Market Sizing
TAM/SAM/SOM framework for estimating addressable market and validating opportunity size.
Definitions
| Metric | Definition | Question It Answers |
|---|
| TAM | Total Addressable Market — everyone who could possibly buy | "What's the theoretical ceiling?" |
| SAM | Serviceable Addressable Market — segment you can actually reach | "What can we realistically target?" |
| SOM | Serviceable Obtainable Market — realistic share in 3 years | "What will we actually capture?" |
+-------------------------------------------------------+
| TAM |
| +---------------------------------------------------+ |
| | SAM | |
| | +-----------------------------------------------+| |
| | | SOM || |
| | +-----------------------------------------------+| |
| +---------------------------------------------------+ |
+-------------------------------------------------------+
When to Use Top-Down vs. Bottom-Up
| Method | Use When | Risk |
|---|
| Top-Down | Industry reports exist; investor pitch; quick estimate | Overestimates SOM |
| Bottom-Up | Sales capacity known; pricing validated; more credible | More work; requires assumptions |
| Both (recommended) | High-stakes decisions; fundraising; board decks | Cross-validate to build confidence |
Always cross-validate both methods and reconcile within 20%. If they diverge by more than that, revisit your assumptions.
Quick Formulas
Top-Down
TAM = (# potential customers) × (annual value per customer)
SAM = TAM × (% your solution can address)
SOM = SAM × (realistic market share % in 3 years)
Bottom-Up
SOM = (# customers you can acquire) × (average deal size)
SAM = SOM / (your expected market share %)
TAM = SAM / (your segment as % of total market)
Example: AI Code Review Tool
## Market Sizing: AI Code Review Tool
### Top-Down
TAM
Global developers: 28M
Using code review tools: 60% → 16.8M
Average annual spend: $300/developer
TAM = $5.04B
SAM
Enterprise only (>500 employees): 8M developers
Willing to pay premium: 40% → 3.2M
SAM = $960M
SOM
Sales capacity supports ~$15M ARR (Year 3)
Realistic market share: 2%
Unconstrained SOM = $960M × 2% = $19.2M
Constrained SOM = min($19.2M, $15M) = $15M
Target accounts Year 1: 50 enterprise deals
Average ACV: $100K
Year 1 ARR: $5M
Year 3 (3× growth): $15M ARR → SOM = $15M
