Every growth plan is a choice about how to pay for the growth. An institution needs more deposits or more loans, and the reflexive way to buy them is a rate promotion. Pay a little more on deposits, charge a little less on loans, and the balances arrive. It works, and plenty of sound institutions run one or two a year and are right to.
There is a second way to buy the same growth, and it never touches the rate. A share of the savers and borrowers a promotion chases are already on your website, shopping at your standard rates. Behavioral intelligence reads that shopping as it happens and responds while the person is still there. That reaches the same goal with no giveaway at all. Two ways to buy one thing, at prices that are not close.
The second price is easy to see. The first is not, because most of what a rate promotion costs never reaches the campaign recap. The question worth answering, before you fund the next one, is what it costs once you total everything the giveaway bought.
“There is a second way to buy the same growth, and it never touches the rate … Behavioral intelligence reads that shopping as it happens and responds while the person is still there.”
What the Giveaway Buys
When a promotional rate goes live, most of the balances it pulls in are not new. They move over from the institution’s own lower-rate accounts, from savers who already banked there and shifted into the better offer. Curinos, which benchmarks deposit performance across the industry, finds that roughly three quarters of promotional balances come from the back book this way, and only about a quarter is genuinely new. The higher rate gets paid mostly on money the institution already had.
The new money comes for the rate. Money that arrives for a rate leaves for a rate. Curinos finds that rate-led acquisition draws the most price-sensitive customers, the ones who move the moment another institution posts a better number, and that these promotions carry 64 percent higher churn over five years. The new money is the money least likely to stay.
A promotion like this reprices money the institution already has and rents money that will not stay. Neither cost shows up when someone totals what the promotion brought in.
These are deposit figures. A loan promotion works the same way, giving up yield instead of paying it.
A Lever Is Not a Strategy
None of this makes a rate promotion a mistake. It is a tool with a real job. When an institution needs funding by a date, a promotion pulls balances in fast and predictably and used that way it earns its cost.
That is the price of one promotion. Run rate as the standing way you grow, and the cost returns every cycle, because rate-bought money leaves when the rate reverts and holding those balances means running the promotion again. Each round costs more than the last, since competitors have matched the old offer and the next one must beat it.
A CFO reading a five-year plan knows the difference between a liquidity move and a growth strategy. A rate promotion is a liquidity move. Treating it as the growth strategy is where an occasional cost turns structural.
The Same Growth, Without the Giveaway
That second way already runs at real institutions. The shoppers a promotion sets out to buy are on the site on their own, and responding to them converts a real share.
At a Southern California credit union, the site began recognizing rate-shoppers who had not yet joined and staying with them across return visits. These were the same rate-shoppers a promotion sets out to buy, reached at the moment they were already looking. Those non-members completed applications at 3.1 times the site baseline. The rates on the page stayed at the institution’s standard posted numbers. The lift came from responding to the intent that was already there.
Results like this vary by institution, and no site should expect another’s figures. The direction, across the places running it, has held.
Price Your Last Promotion
The way to make this concrete is to run the numbers on your own most recent promotion. Pull the promotional rate, the standard rate it sat above, and the volume of balances the promotion carried. If some of those figures sit with treasury rather than marketing, that is the point, because this is a treasury conversation the marketing champion gets to start. Then total the cost the summary leaves out.
Start with the visible giveaway, the spread on the new money. Add the premium paid on the share that moved over from your own accounts, using the industry share as a guide until you can pull your own. Then ask what it costs to hold those balances once the rate reverts, because the money most likely to leave is the money you will pay to attract all over again.
We built a one-page cost model that walks the sequence, with a worked example you can follow and then rerun on your own figures. The output is a single number, the real price of buying growth on rate. That number belongs in the budget conversation, stated in the language the budget owner already speaks.
