Connectivity as a Routing Layer

This reveals how sticky bank linking infrastructure becomes once a consumer app is live at scale. For Square, adding a second aggregator was not just a vendor swap. It meant rebuilding the account linking layer, normalizing different data formats, and asking users to reconnect bank accounts in flows where reliability and conversion matter more than marginal coverage gains or pricing leverage.

• The core lock in is both technical and behavioral. Fintechs that start with one provider build their onboarding, retries, and downstream data models around that provider. Moving later requires a multiplexer layer and standardized schemas across aggregators, which can consume 20% to 30% of engineering time in multi provider setups.
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• For products like Venmo and Cash App, the job is usually simple bank auth for ACH funding, not a full financial dashboard. That makes one strong U.S. aggregator good enough. The biggest pain of going multi aggregator is often forcing users to re authenticate because providers like Plaid do not hand app developers user bank credentials.
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• The payoff is real but narrow. A second aggregator can improve contract leverage and rescue unsupported or failing institutions, but net new coverage is smaller than it looks because Plaid, Yodlee, Finicity, and MX overlap heavily and often share or resell long tail connectors. That limits the benefit relative to the migration cost.
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Going forward, the winners in financial data will be the companies that treat connectivity as a routing layer instead of a single vendor decision. As open banking APIs spread and raw access becomes more interchangeable, value will shift toward orchestration, fallback logic, and enrichment, which is exactly why aggregator of aggregators products are emerging.