Why do large groups rationalize their bank accounts and relationships, and what's the trade-off?

Sprawling groups accumulate hundreds of bank accounts across many banks and countries, which is costly and risky: fees and minimum balances multiply, idle cash gets trapped in many accounts, visibility and forecasting suffer, KYC/onboarding and account-maintenance burden is heavy, and fraud/control risk rises with more access points. Rationalization consolidates to fewer accounts and a core group of relationship banks — improving cash visibility and pooling, cutting fees and KYC effort, standardizing controls and connectivity (one platform/host-to-host, or a payment factory), and concentrating wallet to get better service and credit support from key banks. The trade-off: don't over-concentrate — you need enough banks for counterparty diversification (deposit/credit risk), local presence where required by regulation or operations, backup if a bank withdraws, and to maintain competitive tension on pricing. So the goal is the minimum efficient set: few enough to be efficient and visible, enough to be resilient and locally compliant. It's a recurring treasury optimization, often alongside implementing pooling or an in-house bank.