How does a Top-Down approach to estimating total addressable industry market size differ from a Bottom-Up approach?

[ A ]Top-Down measures only employee headcounts, whereas Bottom-Up measures only central bank foreign exchange reserves.

[ B ]Top-Down is used exclusively for liquidated companies, while Bottom-Up is used exclusively for foreign sovereign debt.

[ C ]Top-Down starts with macroeconomic data/total target population and filters down by penetration and average spending per user; Bottom-Up aggregates operational capacities and sales data of all individual competing producers in the industry.[ CORRECT ]

[ D ]Both approaches are identical formulas that multiply the stock exchange index by the statutory corporate tax rate.

Takeaway

Option C is correct: Top-Down starts with macroeconomic data/total target population and filters down by penetration and average spending per user; Bottom-Up aggregates operational capacities and sales data of all individual competing producers in the industry.

Derivation

Market sizing quantifies industry growth potential: (1) Top-Down Approach begins with broad macroeconomic data, total population demographics, or industry total addressable market (TAM), applying percentage penetration rates and average revenue per user (ARPU) to estimate market size. (2) Bottom-Up Approach aggregates granular operating numbers—unit production volumes, store counts, hospital bed capacities, or company sales filings—across all existing market participants to build up the aggregate industry size. This tests market estimation methods. The common trap is confusing macro filtering with micro firm aggregation.

Why the others fail

A — Top-Down measures only employee headcounts, whereas Bottom-Up measures only central bank foreign exchange reserves.

Market sizing quantifies industry economic sales potential, having no connection to isolated employee headcounts or forex reserves.

B — Top-Down is used exclusively for liquidated companies, while Bottom-Up is used exclusively for foreign sovereign debt.

Top-down and bottom-up sizing frameworks apply to active commercial industries, not exclusively to liquidations or sovereign debt.

D — Both approaches are identical formulas that multiply the stock exchange index by the statutory corporate tax rate.

Market sizing utilizes fundamental demographic and corporate operational data rather than multiplying stock indices by tax rates.