Calculate TAM/SAM/SOM for market opportunities using top-down, bottom-up, and value theory methodologies. Use this skill when sizing markets, estimating addressable revenue, validating market opportunity for a new venture, or building investor-ready market analysis for a startup pitch or business plan.
Install with the open skills CLI (global, non-interactive — available in every Claude Code session):
npx skills add wshobson/agents --skill "market-sizing-analysis" -g -a claude-code -yOr manually — clone and copy the skill directory (SKILL.md + companion files):
git clone --depth 1 https://github.com/wshobson/agents /tmp/agents && cp -r /tmp/agents/plugins/startup-business-analyst/skills/market-sizing-analysis ~/.claude/skills/market-sizing-analysis-wshobsonThis skill is a directory: SKILL.md is the entry point; the files below ship with it.
---
name: market-sizing-analysis
description: Calculate TAM/SAM/SOM for market opportunities using top-down, bottom-up, and value theory methodologies. Use this skill when sizing markets, estimating addressable revenue, validating market opportunity for a new venture, or building investor-ready market analysis for a startup pitch or business plan.
version: 1.0.0
---
# 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.
You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.
Use when you have a written implementation plan to execute in a separate session with review checkpoints
Use when executing implementation plans with independent tasks in the current session