Market Sizer
SkillDev toolsTAM/SAM/SOM calculation with data source integration (CB Insights, PitchBook, etc.)
Instructions available. Your AI can read the instructions. Execution depends on the setup they require.
Account requirements not reviewed. Check the skill instructions before use; ahel provides instructions and does not run this skill.
Add ahel to your AI once: Claude, ChatGPT, Cursor, Claude Code or Codex. Then ask it to use this.
Then ask your AI: use the Market Sizer skill
What this skill tells your AI
The instructions your AI receives, as published by a5c-ai/babysitter in library/specializations/domains/business/venture-capital/skills/market-sizer/SKILL.md and read by ahel’s review.
Overview
The Market Sizer skill provides systematic Total Addressable Market (TAM), Serviceable Addressable Market (SAM), and Serviceable Obtainable Market (SOM) calculations. It integrates with industry data sources to build defensible market sizing analyses for investment evaluation.
Capabilities
TAM/SAM/SOM Calculation
- Top-down market sizing from industry reports
- Bottom-up market sizing from unit economics
- Value theory sizing from willingness to pay analysis
- Triangulation across multiple methodologies
Data Source Integration
- CB Insights market data and industry reports
- PitchBook market maps and sizing
- Gartner, Forrester, and industry analyst reports
- Government statistics and census data
- Public company filings and disclosures
Market Segmentation
- Geographic market segmentation
- Customer segment sizing
- Use case and application segmentation
- Adjacent market opportunity mapping
Growth Analysis
- Historical market growth rates
- Growth driver identification and analysis
- Market maturity assessment
- Disruption and substitution risk evaluation
Usage
Calculate Market Size
Input: Market definition, methodology preference, data sources
Process: Gather data, apply sizing methodology, triangulate
Output: TAM/SAM/SOM estimates with methodology documentation
Validate Company Claims
Input: Company's market size claims, their methodology
Process: Independent sizing, compare against company claims
Output: Validation assessment, discrepancy analysis
Map Adjacent Markets
Input: Core market definition, expansion vectors
Process: Size adjacent opportunities, assess accessibility
Output: Expansion opportunity matrix with sizes
Forecast Market Growth
Input: Current market size, growth drivers, timeline
Process: Model growth scenarios with assumptions
Output: Market forecasts with confidence intervals
Sizing Methodologies
| Methodology | Best For | Approach |
|---|---|---|
| Top-Down | Established markets | Industry reports, public data |
| Bottom-Up | New markets | Unit counts x pricing |
| Value Theory | Disruption plays | Value created x capture rate |
| Comparable | Adjacent markets | Analogy to similar markets |
Integration Points
- Commercial Due Diligence: Feed market size into DD analysis
- Deal Scoring Engine: Incorporate market scores
- VC Method Valuation: Support exit multiple assumptions
- IC Memo Generator: Include market analysis in memos
Best Practices
- Always triangulate with multiple methodologies
- Clearly document assumptions and data sources
- Define market boundaries precisely
- Distinguish between current and future market size
- Account for market creation vs. capture scenarios
Signals
- GitHub stars
- 2k
- Forks
- 112
- Last commit
- Sep 2026
Advanced
- Item type
- skill
- Key
market-sizer- Source
- github.com/a5c-ai/babysitter
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