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Unit Economics

Stripping a business down to its irreducible economic unit and asking: does this unit cover its costs, contribution margin, allocated overhead, and capital charge?

If the unit doesn't make money, the company doesn't, no matter how much scale is achieved. Unit economics is the antidote to "we'll grow into profitability" claims that destroyed enormous shareholder capital in growth-investor cycles.

What "unit" means

The economic unit varies by business:

  • Per customer / subscriber: SaaS, telecom, streaming, banking
  • Per store / location: retail, restaurants, hotels
  • Per transaction: payment processing, marketplace
  • Per unit shipped / produced: manufacturing, mining, refining
  • Per route / mile / lane: transportation
  • Per well / mine / plant: extraction
  • Per gigawatt-hour: power generation
  • Per square foot: real estate, certain retail
  • Per active user (DAU/MAU): advertising-supported platforms

Pick the unit that best reflects the underlying economics. For some businesses, multiple units are meaningful (per store + per customer for retail).

The structure

For each unit:

Revenue per unit

  • Average revenue (with mix considerations)
  • Trend
  • Comparability across units (segment, geography, channel)

Variable costs per unit

  • Direct cost of goods or service
  • Sales commission, transaction cost
  • Variable labor

Contribution margin per unit

= Revenue − Variable cost. What each additional unit contributes toward fixed cost and profit.

Allocated fixed cost per unit

  • Per-unit allocation of marketing, R&D, G&A
  • Per-unit allocation of facility / overhead

Operating margin per unit

= Contribution − Allocated fixed. What each unit earns operationally.

Capital charge per unit

  • Per-unit allocation of capital invested (working capital + PP&E + intangibles)
  • Capital × cost of capital = capital charge

Economic profit per unit

= Operating margin − Capital charge. This is the real metric. If positive, the unit creates value; if negative, the unit destroys it regardless of how it looks on operating-income metrics.

SaaS unit economics

For SaaS, the standard set:

  • CAC (Customer Acquisition Cost): sales & marketing spend / new customers acquired
  • ARPU (Average Revenue Per User): annual recurring revenue / customers
  • Gross margin (after hosting, support, COGS)
  • LTV (Lifetime Value): ARPU × Gross margin / churn
  • LTV/CAC ratio: target > 3.0
  • Payback period: CAC / (ARPU × Gross margin), in months; target < 24 months
  • Net Revenue Retention: ARR retained + expansion / starting ARR; target > 100%

Be careful with SaaS metrics:

  • CAC often understates by ignoring corporate marketing, brand spend, etc.
  • LTV assumes stable retention, which often deteriorates with growth
  • "Magic Number" (new ARR / S&M spend) is more honest than LTV/CAC

Retail / restaurant unit economics

The "4-wall" view of a single store:

  • Revenue per store (average + comp)
  • 4-wall gross margin
  • 4-wall operating margin (after labor, rent, utilities, repairs, royalties)
  • Average ticket × traffic
  • Capex per store opening
  • Payback period (years to recover capex from 4-wall cash flow)

For franchise vs. owned, the calculations differ:

  • Owned: full unit economics including all costs and capex
  • Franchised: royalty stream is the corporate revenue; 4-wall margin is the franchisee's

A franchise model is attractive when franchisees can earn good returns and the franchisor earns royalty on top. If franchisee economics collapse, the system collapses regardless of franchisor accounting.

Network / two-sided unit economics

For marketplaces and platforms:

  • Take rate: revenue / GMV
  • Liquidity by market / geography
  • Cohort retention by side (buyers and sellers)
  • Acquisition cost by side
  • Cross-side leverage: revenue from side A per unit of side B

Where unit economics destroy theses

"Negative unit economics with promise of scale"

A unit losing money is not improved by adding more units; it makes the company lose more money. The classic VC-funded growth-at-any-cost businesses (food delivery, certain DTC, certain ride-share at trough) often had unit economics that never improved as expected.

Test: at scale, what would unit economics look like? If the answer requires unrealistic improvements in any of revenue, variable cost, fixed allocation, the thesis fails.

Hidden fixed cost growing with units

Sometimes "fixed costs" grow with units in disguise (regulation costs scaling with volume, customer service scaling). Test: which costs truly stay fixed when units double?

Capital intensity escalating

Sometimes capital intensity grows with scale (capex per unit rises rather than falls). Test: which step in the chain requires capital proportional to volume?

Marginal customer profitability declining

The first 10% of customers are profitable; the next 90% may not be. The blended average masks the marginal economics. For SaaS: as you scale through the customer base, are you adding profitable customers or unprofitable ones?

Deep-value applications

Identifying robust unit economics in unloved sectors

Stable businesses with strong unit economics often get unloved in narrative cycles. The deep-value investor finds them by working bottom-up from unit economics, ignoring the sector narrative.

Stress-testing growth-investor theses

For names that growth investors are excited about, working through the unit economics often reveals the implied terminal economics are unrealistic. Selling pressure follows when the market sees what the unit-economic analysis showed.

Cost-curve mapping

For commodity businesses, unit economics by producer reveals the cost curve. The lowest-unit-cost producer survives cycles; higher-cost ones don't.

Output

A unit economics analysis includes:

  1. Unit definition
  2. Revenue per unit with trend
  3. Cost structure per unit (variable, allocated fixed, capital charge)
  4. Economic profit per unit
  5. Sensitivity to key drivers (price, volume, cost)
  6. Trajectory — improving, stable, deteriorating
  7. Implications for the firm's value at maturity

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