Market-Sizing Estimate: Users and Revenue Pool for an Improved Debit Card

Estimate the potential market size for an improved debit card, and walk through how you reach the number. ```hint Decide what you are counting Settle whether the answer is a number of cardholders or a yearly revenue figure before multiplying anything. For revenue, how often a debit card is used matters as much as how many people carry one. ``` ### Clarifying Questions - Should I size one country, such as the US, or the global market? - Do you want the market as a number of potential cardholders, as yearly revenue to the card issuer, or both? - What makes the card "better": no fees, rewards, earlier access to deposited pay, stronger fraud protection? And who is it aimed at? - Is it issued by a large established bank or by a smaller bank or fintech? In some countries the fee a debit card earns on each purchase is regulated differently depending on the issuer's size. ### What a Strong Answer Covers - A clear scope (geography, unit, target segment) and an equation laid out before any numbers - Labeled, round assumptions for population, debit card ownership and card usage - Correct arithmetic from the total market down to the share a new card could realistically win - A sanity check from a second angle, such as total transaction counts - How the definition of "better" changes the economics, for example whether rewards can be paid for by what the card earns ### Follow-up Questions - How would your estimate change if the card were aimed at teenagers and their parents? - If the card paid cash back on every purchase, how would you check whether it could be profitable? - Which assumption is your estimate most sensitive to, and how would you validate it?