Market Sizing Analysis
Calculates TAM, SAM, and SOM using three methodologies: top-down from industry reports, bottom-up from customer segments, and value theory from willingness to pay. Walks you through the complete framework with formulas, data sources, and validation checks. Use it when building investor decks, validating startup opportunities, or sizing markets for business plans. The bottom-up methodology is most credible with VCs since it builds from actual customer data rather than industry estimates. Includes realistic penetration rates and warns against common red flags like claiming more than 10% market share as a new entrant.
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- Aug 21, 2026
Install
$ npx -y skills add wshobson/agents --skill market-sizing-analysis --agent claude-codeInstalls into .claude/skills of the current project.
Files
Market Sizing Analysis
Comprehensive market sizing methodologies for calculating Total Addressable Market (TAM), Serviceable Available Market (SAM), and Serviceable Obtainable Market (SOM) for startup opportunities.
Overview
Market sizing provides the foundation for startup strategy, fundraising, and business planning. Calculate market opportunity using three complementary methodologies: top-down (industry reports), bottom-up (customer segment calculations), and value theory (willingness to pay).
Core Concepts
The Three-Tier Market Framework
TAM (Total Addressable Market)
- Total revenue opportunity if achieving 100% market share
- Defines the universe of potential customers
- Used for long-term vision and market validation
- Example: All email marketing software revenue globally
SAM (Serviceable Available Market)
- Portion of TAM targetable with current product/service
- Accounts for geographic, segment, or capability constraints
- Represents realistic addressable opportunity
- Example: AI-powered email marketing for e-commerce in North America
SOM (Serviceable Obtainable Market)
- Realistic market share achievable in 3-5 years
- Accounts for competition, resources, and market dynamics
- Used for financial projections and fundraising
- Example: 2-5% of SAM based on competitive landscape
When to Use Each Methodology
Top-Down Analysis
- Use when established market research exists
- Best for mature, well-defined markets
- Validates market existence and growth
- Starts with industry reports and narrows down
Bottom-Up Analysis
- Use when targeting specific customer segments
- Best for new or niche markets
- Most credible for investors
- Builds from customer data and pricing
Value Theory
- Use when creating new market categories
- Best for disruptive innovations
- Estimates based on value creation
- Calculates willingness to pay for problem solution
Detailed patterns and worked examples
Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.
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Details
- Repository
- github.com/wshobson/agents
- Categories
- Productivity & Planning, Sales & Marketing
