# Market Sizing > TAM/SAM/SOM estimation with top-down and bottom-up approaches. Use when sizing a market opportunity, building a business case, or estimating revenue potential. - **Type:** Skill - **Install:** `agentstack add skill-uthumany-uthy-legacy-os-market-sizing` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [uthumany](https://agentstack.voostack.com/s/uthumany) - **Installs:** 0 - **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [uthumany](https://github.com/uthumany) - **Source:** https://github.com/uthumany/uthy-legacy-os/tree/main/skills/discovery/market-sizing - **Website:** https://uthumany.github.io/uthy-legacy-os/ ## Install ```sh agentstack add skill-uthumany-uthy-legacy-os-market-sizing ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # Market Sizing ## Overview Market sizing answers one question: **how big is this opportunity?** It's a critical input for prioritization, fundraising, and strategic planning. This skill guides you through TAM (Total Addressable Market), SAM (Serviceable Addressable Market), and SOM (Serviceable Obtainable Market) estimation using both top-down (macro data) and bottom-up (unit economics) approaches. ## When to Use - Evaluating whether to enter a new market - Building a business case for a new product - Preparing for investor pitches or board reviews - Comparing multiple opportunity areas - Don't use for: feature-level decisions (too noisy), already-proven markets (sizing is implied) ## Instructions ### 1. Define Your Market **Top-down approach**: 1. Start with a broad market number (industry reports, analyst data) 2. Apply filters to narrow to your addressable segment 3. Adjust for geography, business size, or other constraints **Bottom-up approach** (preferred for accuracy): 1. Define your target customer unit (user, seat, account, transaction) 2. Estimate number of target customers 3. Multiply by expected price per unit 4. Adjust for adoption rate over time ### 2. Calculate TAM TAM = total revenue opportunity if you had 100% market share. - Top-down: Find industry revenue → multiply by your segment's share - Bottom-up: (Total potential customers × Price per customer/year) - Be explicit about your assumptions — document each one ### 3. Calculate SAM SAM = the portion of TAM you can reach with your current or planned offering. - Apply filters: geography, segment, use case compatibility - Example: If TAM is $10B but you only serve mid-market US companies, SAM might be $500M ### 4. Calculate SOM SOM = the portion of SAM you can realistically capture in the near term (3-5 years). - Based on capacity: sales team size, distribution channels, marketing budget - Based on competitive position: realistic market share given your differentiation - SOM is usually 1-10% of SAM for new entrants ### 5. Sensitivity Analysis Market sizing is guesswork with math. Run scenarios: - **Conservative**: Lower end of estimates, slower adoption - **Base case**: Best-guess estimates - **Optimistic**: Higher adoption, faster growth - For each scenario, show the key drivers that would make it true ### 6. Document Assumptions Every estimate relies on assumptions. List them explicitly: - "We assume 10% of Fortune 500 companies will adopt" - "Based on Forrester report sizing the market at $X" - "Assumes $50/user/month pricing with 20% annual discount for enterprise" ## Sample Output Market sizing for a team documentation tool: - **TAM**: $12B (global knowledge management spend, per Gartner 2024) - **SAM**: $1.8B (mid-market tech companies with 50-500 employees) - **SOM**: $36M (2% of SAM over 3 years, given sales capacity of 12 reps) - **Bottom-up sanity check**: 20,000 companies × 100 users × $15/user/month × 12 months = $36M/year ✓ - **Key assumption**: 40% gross margins, $15/user/month pricing ## Common Pitfalls 1. **TAM vanity** — A $1B TAM doesn't matter if you can only reach $10M of it 2. **Garbage in, garbage out** — Bad assumptions produce precise-looking wrong answers 3. **Confusing SAM with SOM** — SAM is reachable, SOM is capturable. These are very different 4. **Static sizing** — Markets grow and shrink. Use growth rates, not single-year snapshots 5. **Bottom-up vs. top-down divergence** — If they differ by 10x, your assumptions are wrong ## Verification Checklist - [ ] TAM documented with source and methodology - [ ] SAM calculated with explicit reachability filters - [ ] SOM based on realistic capacity and market share estimates - [ ] Assumptions listed and challenged (at least 5) - [ ] Sensitivity analysis run (conservative, base, optimistic) - [ ] Bottom-up and top-down estimates within 2x of each other ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [uthumany](https://github.com/uthumany) - **Source:** [uthumany/uthy-legacy-os](https://github.com/uthumany/uthy-legacy-os) - **License:** MIT - **Homepage:** https://uthumany.github.io/uthy-legacy-os/ Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-uthumany-uthy-legacy-os-market-sizing - Seller: https://agentstack.voostack.com/s/uthumany - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.