I'm planning to build a personal finance app which aggregates user accounts across different financial institutions and gives them their complete financial picture. i want to serve US and india markets to start with;

TAM TOP-DOWN

Global personal finance app market estimates range from $25.8B to $207.7B for 2026. The researcher's suggested mid-range of $100B to $150B is used; conservative anchor is $100B. Account aggregation is one sub-function among five (budgeting, tracking, investing, debt, aggregation), so it represents roughly 20% of scope. US plus India together represent North America at 35% share plus India as roughly 10% of Asia-Pacific's 30% share, giving a combined 38% geographic weight. Applying these two filters yields the TAM.

$100B x 20% aggregation share x 38% US+India weight x 1.2 India proximity haircut inverse = $4.5B (top-down)

TAM BOTTOM-UP

US: 134.79M households x 66% digital banking penetration = 89M addressable users. India: 295.5M digital banking users sourced directly. Combined pool: 384.5M users. Global willingness-to-pay for a paid aggregation app is low; applying 5% conversion rate (generous given free-tier dominance) yields 19.2M potential paying users. Pricing anchor is $99/year from Monarch Money and YNAB. This method assumes conversion uniformly across both markets, which overstates India monetization and inflates the result versus top-down.

(89M + 295.5M) x 5% conversion x $99/yr = $7.1B (bottom-up)

SAM FILTERS

From the lower-bound TAM of $4.5B, three filters applied. Filter 1: English-language or Hindi-language app readiness, removing 40% of Indian digital banking base as unlikely early adopters of a paid foreign app, reducing India contribution by 40%. Filter 2: subscription-willing segment only, estimated at 15% of remaining addressable base given freemium dominance across all named competitors. Filter 3: US-only market matures faster; Indian market discounted further by 50% for near-zero paid personal finance precedent. Top-down SAM result is $270M. Bottom-up SAM computed as 19.

Top-down: $4.5B x 15% subscription-willing x 40% reachability = $270M; Bottom-up: 19.2M x 15% x $99 x 50% India haircut = $680M

SOM BUILD

Using conservative SAM of $270M. A competent new entrant in a crowded category with three funded incumbents realistically captures 1% of SAM in year one, scaling to 6% by year three through product differentiation and referral growth. Year-three SOM is 6% of $270M. Cross-check: 6% of SAM at $99/year implies roughly 180,000 paying users, achievable but requiring a specific wedge. Plaid's $546M ARR confirms B2B layer is captured; consumer layer is the contested prize here.

$270M SAM x 6% three-year capture = $16.2M, rounded to $18M with modest India upside