The Real Math on Why Big Banks Can Afford to Pay You Nothing

Two SwitchWize pieces already document the gap itself: big banks pay about 0.01% on standard savings while top online accounts pay a hundred times more, and deposit beta explains why big banks pass through so little of a Fed rate move. Both stop at the surface answer: big banks don't have to pay more because their customers don't leave. This piece goes one level deeper, into the actual mechanism, because "they don't have to" understates something more deliberate. A megabank's low rate is not a lapse. It is the maintenance of an asset.

The deposit base is a formally valued asset, not just a balance

When one bank acquires another, an appraiser puts a specific dollar figure on the acquired bank's checking and savings relationships, separate from the cash balances themselves. The accounting term is a core deposit intangible: the present value of the future cost savings from funding the balance sheet with cheap, sticky retail deposits instead of a more expensive alternative, discounted for how long those deposits are expected to stay and how little they cost to keep.

That value only exists because the deposits are cheap and sticky at the same time. A bank that raised its savings rate to the market top would still have sticky deposits, but they would no longer be cheap, and the intangible value would shrink. From inside the bank's own balance-sheet math, every basis point of savings APY not paid is value retained on an asset the bank already owns. A near-zero rate is not the bank failing to notice the market. It is the bank protecting a line item.

The deposit doesn't actually have to come from you

The second piece of the mechanism: a large bank is not dependent on retail deposit pricing to fund itself, because retail deposits are one funding source among several. Banks can, and routinely do, fund balance-sheet growth through wholesale channels: advances from a Federal Home Loan Bank, the fed funds and repo markets, and brokered deposits, deposits sourced through a broker at whatever the going market rate is, deployed specifically when the bank wants to grow its balance sheet faster than sticky retail deposits allow.

That optionality is exactly what changes the incentive. A bank that genuinely needed every dollar of retail deposits to fund its lending would be forced to compete on rate or shrink. A bank with wholesale alternatives can instead let its retail savings rate sit near the floor indefinitely, funding incremental growth through the wholesale market only when it is cheaper than raising the retail rate for every existing depositor. Online banks, several of which lack the branch network, brand recognition, or wholesale funding relationships of a money-center bank, do not have the same optionality, which is part of why they compete on rate instead.

Why raising the rate for everyone doesn't pencil out

The clearest way to see the actual math: imagine a megabank with, say, $500 billion in retail savings deposits. Some meaningful share of depositors are price-sensitive and would leave for a better rate if the bank doesn't offer one; call this group the switchers. The much larger remainder stays regardless of the rate: paychecks land there by default, mortgage escrow accounts sit there because the mortgage does, a small business keeps an operating balance there for the branch and the banker relationship, or the balance is simply too small or the inertia too strong for the account holder to act on.

Raising the rate to compete does not let the bank pay more to just the switchers. It has to pay the new, higher rate on the entire base, switchers and stayers alike, because a bank cannot legally offer two different standard savings rates to two customers based on how likely each is to leave. The cost of retaining the price-sensitive minority is paid on the inertia-driven majority too. For a base that is mostly inertia-driven, that trade rarely clears: the bank would be handing over real money to millions of depositors who were never going to leave anyway, to prevent a smaller number who might.

This is, in plain terms, price discrimination by customer attentiveness rather than a formal, itemized one. Airlines charge business travelers who book late more than leisure travelers who shop months ahead for the identical seat. A megabank effectively does the same thing with your deposit: whoever doesn't shop pays the full price, in foregone interest, and whoever does gets the market rate somewhere else.

What actually breaks the arrangement

The one thing that reliably erodes a core deposit intangible is depositors leaving. Every dollar that moves from a 0.01% account to a market-rate one is a dollar the bank can no longer count as cheap funding, and if enough depositors move at once, the intangible's own value on the bank's books declines along with it. That is precisely why megabanks keep the retail experience convenient, branches, ATMs, a familiar app, cross-sold checking and credit products, rather than the rate competitive: convenience keeps the intangible intact at a far lower cost than a rate increase would.

None of this is a reason to stay. It is the specific mechanism behind why the rate gap the Bank Gap Index tracks has persisted through rate-cut cycles and rate-hike cycles alike: it was never really about the Fed. Money Map prices the gap on your own balance in under a minute, and the fix costs nothing but the decision to actually look.

Methodology and sourcing

The core deposit intangible concept is a standard bank M&A accounting and regulatory-appraisal term, used by the OCC, FDIC, and bank appraisers in evaluating acquisitions; this piece explains the concept and its incentive effects rather than citing a specific bank's disclosed intangible value, which is not something SwitchWize independently verifies. Federal Home Loan Bank advances and brokered deposits are real, well-documented bank funding channels described in FHLB and FDIC public materials. The illustrative $500 billion example and the switcher/stayer framing are simplified for explanation, not a specific bank's actual figures. This page is informational, not financial advice.