Interactive Tools

Certificate Repricing Engine

What does a rate increase actually cost you?

Retention is a curve, not a cliff. Modeling it as a sigmoid instead of a linear guess is the whole difference.

What it does

An interactive model of certificate repricing economics: move the posted renewal rate and see, live, how much balance is retained, how much walks, and what the increment actually costs per incremental dollar retained, benchmarked against the cost of replacing that funding with borrowings.

What this demonstrates

Modeling deposit retention as a function of rate (a sigmoid retention curve, not a linear guess), and building an interactive tool that makes a cost-of-funds tradeoff visible in real time instead of buried in a spreadsheet.

Quantitative modeling of deposit retention behavior
ALM-style cost-of-funds tradeoff analysis (repricing vs. borrowing)
Interactive, real-time front-end tool built directly on the underlying model

Live demo

Try it yourself

This one has a working, interactive version below. Everything recalculates live as you move the controls.

Illustrative data

CERTIFICATE REPRICING

What does a rate increase actually cost you?

Move the slider. Every number below recalculates live, including the one most CFOs don’t expect.

A $2B credit union has $200.0M in certificates maturing next quarter, across roughly 5,750 certificates.

Posted 12-month renewal rate3.90%

3.90%4.60%

Balance retained

$118.4M

Balance walking out

$81.6M

Annual cost of the increment

Incremental balance retained

$0.0M

Cost per incremental dollar retained

0.00¢

No increment applied. Nothing to compare yet.

The reveal

Who you’re actually paying for

Would have renewed anyway — $118.4MRetained because of the increment — $0.0MWalking out — $81.6M

Paid annually to the group that would have stayed anyway

Broad-based repricing pays every renewing depositor the new rate, including the $118.4M that would have renewed at 3.90% anyway.

No increment is applied yet. This is your standard renewal rate, the baseline everything else on this page is measured against.

Curious how this was built?

Reach out, I’m happy to walk through the approach and compare notes with other analysts and data folks tackling similar problems.

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