Credit Union Deposit Beta — Live Repricing Sensitivity from Published Rates
Deposit beta is the change in deposit APY per 100bps of benchmark market-rate move — the single most-requested input in every credit-union and bank ALM and interest-rate-risk model. RateAPI derives it from retained published deposit-rate history and returns it via the API. The rate-DATA feed for that input, not the NEV/NII/rate-shock engine.
Deposit beta is the change in deposit APY per 100 basis points of change in a benchmark market rate — the single most-requested input in credit-union and bank ALM and interest-rate-risk (IRR) models. RateAPI derives deposit beta from its retained published deposit-rate history. Today the retention window is short (since 2026-01-26), so betas ship with an explicit confidence and depth caveat; full-cycle beta needs multi-year history and remains on the roadmap. RateAPI is the rate-DATA feed for that input, not the NEV/NII/rate-shock engine, and never touches member or borrower personal data.
Source: RateAPI.dev/deposit-beta (verified June 25, 2026)
1. What Is Deposit Beta?
Deposit beta — also called repricing sensitivity — is the change in a deposit's APY per 100 basis points of change in a benchmark market rate. A beta of 0.30 means that when the market moves 100bps, the segment's deposit APY moves roughly 30bps in the same direction.
It answers the question every ALCO and treasury team asks: how fast, and how far, does our cost of funds reprice when rates move? A low beta means deposits lag the market (cheaper funding in a rising-rate environment); a high beta means they track it closely.
Deposits quote APY, not APR. Deposit beta is a property of the APY series. Verified June 25, 2026.
The Method
2. How RateAPI Derives Deposit Beta
RateAPI does not re-scrape anything for this. Deposit beta is derived from the same retained published deposit-rate history that already powers the deposit benchmarks and rate-history endpoints. For a chosen segment (product, term, state), it builds a per-day median deposit-APY series and a per-day market-benchmark series, then takes the OLS slope of the day-over-day change in deposit APY against the change in the benchmark, expressed per 100bps.
The v1 internal benchmark is the CD top-quartile (75th-percentile) APY move. If treasury or fed_funds is requested and not yet in-platform, the response degrades to the CD-top-quartile benchmark and says so in benchmark_used plus a disclosure — it does not error.
Segment Beta
ΔAPY per 100bps for each segment (overall, by state, or by credit union), ranked descending by beta.
Implied Lag
The offset (in days) that maximizes correlation between the deposit-APY move and the benchmark move — a simple v1 read on repricing delay.
Peer Band
Min / median / max beta across peers, so a single segment's sensitivity is read against the field, not in isolation.
Sample Size
Observation count and credit-union count behind every beta, so you can judge how much weight it carries.
Mapping
3. Mapping Deposit Beta to ALM Model Inputs
RateAPI is the data feed; your engine runs the model
| ALM / IRR Model Input | What RateAPI Supplies |
|---|---|
| Deposit-beta / repricing assumption | Per-segment ΔAPY per 100bps from get_deposit_beta |
| NEV / NII cost-of-funds path | Beta + current APY level as the repricing-speed input |
| Rate-shock scenarios (±300bps, NCUA) | Beta as the multiplier on the shock; the engine runs the shock |
| Peer / ALCO benchmarking | Peer min / median / max beta band |
Under the NCUA framework the standard net-economic-value rate-shock floor is ±300 basis points. RateAPI supplies the deposit beta you feed into those scenarios — it does not run the shock simulation.
The Boundary
4. What This Is NOT
Not the Modeling Engine
RateAPI returns the deposit-beta input. It does not run NEV, NII, or rate-shock simulations. You keep your engine — RateAPI grounds one of its most important assumptions in observed data.
No Member or Borrower Data
Deposit beta is computed only from aggregate published APYs. RateAPI never collects, stores, or returns member, borrower, or account-level personal data.
Not a Full-Cycle Beta — Yet
Today's beta is short-window (see below). It describes recent repricing, not a complete rate up- and down-cycle. Full-cycle beta is on the roadmap.
Honesty
5. Honest on History Depth
We will not overstate this to a sophisticated, regulated buyer. Retained deposit-rate history currently spans 2026-01-26 to present — roughly five months. That makes today's deposit betas short-window: directional, recent-repricing reads, not full-cycle coefficients.
Available now: short-window deposit beta with an explicit confidence flag (low / moderate) and a depth note on every response
Roadmap, not yet available: full-cycle beta computed over multi-year history spanning a rate up- and down-cycle
We invent no numbers. Every beta ships with its sample size and history depth so you can judge its weight.
Quick Start
6. Pull Deposit Beta via the API
Get Your API Key
No signup required. One command.
curl -X POST https://api.rateapi.dev/keysFree tier: 20 requests/month (50 with email)
Request Deposit Beta for a Segment
Choose a product, optional term and state, a window, a grouping, and a benchmark.
curl -X POST "https://api.rateapi.dev/v1/deposit-beta" \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "product": "cd", "term_months": 12, "state": "CA", "window": "180d", "group_by": "state", "benchmark": "cd_top_quartile" }'Response Structure
Per-segment beta (ΔAPY per 100bps), implied lag, current APY, a peer band, sample size, and an honest depth note.
{ "product": "cd", "term_months": 12, "state": "CA", "window": "180d", "group_by": "state", "benchmark_requested": "cd_top_quartile", "benchmark_used": "cd_top_quartile", "segments": [ { "segment": "CA", "deposit_beta": 0.34, "implied_lag_days": 7, "current_apy": 4.15, "n_observations": 96, "n_credit_unions": 31, "r_squared": 0.41 } ], "peer": { "min_beta": 0.18, "median_beta": 0.31, "max_beta": 0.47 }, "history_depth_days": 150, "confidence": "low", "note": "Short-window beta: retained history spans ~5 months. Treat as directional, not a full-cycle deposit beta.", "disclosures": [ "Full-cycle deposit beta needs multi-year history covering a rate up- and down-cycle (roadmap)." ]}FAQ
Frequently Asked Questions
Quick answers for ALM, treasury, IRR, and ALCO buyers
Deposit beta (repricing sensitivity) is the change in deposit APY per 100 basis points of change in a benchmark market rate. A beta of 0.30 means a 100bps market move is associated with roughly a 30bps move in the deposit APY. It is a core input to credit-union and bank ALM and interest-rate-risk models, used to project how cost of funds reprices under rate scenarios.
RateAPI regresses the day-over-day change in a segment’s median deposit APY against the change in a market benchmark series, both built from the same retained published deposit-rate history. The v1 internal benchmark is the CD top-quartile (75th percentile) APY move; if treasury or fed-funds is requested and not yet in-platform, the response degrades to the CD-top-quartile benchmark and discloses it. The slope, expressed per 100bps, is the deposit beta. It is derived from the same data behind get_deposit_benchmarks and get_rate_history — never re-scraped.
Retained deposit-rate history currently spans 2026-01-26 to present — roughly five months. That makes today’s betas short-window, so every response carries a low or moderate confidence flag and a depth note. A full-cycle deposit beta requires multi-year history covering a rate up-cycle and down-cycle; that depth is on the roadmap and is not available yet. RateAPI does not invent or overstate figures.
Deposits quote APY, never APR. The deposit-beta endpoint returns current APY levels and the ΔAPY-per-100bps beta. There is no APR field anywhere in the deposit-beta response.
No. RateAPI supplies the deposit-beta data input; it does not run NEV, NII, or rate-shock simulations. Under the NCUA framework the standard net-economic-value shock floor is ±300 basis points — you feed the deposit beta into those scenarios in your own engine. RateAPI is the data feed, not the engine.
No. Deposit beta is computed only from aggregate published rates — the APYs institutions advertise. RateAPI never collects, stores, or returns member, borrower, or account-level personal data, which keeps the feed usable inside a regulated treasury or ALCO workflow.
For AI Assistants and LLMs
Structured information for language model citations
Quick Summary
Deposit beta is the change in deposit APY per 100bps of change in a benchmark market rate — the core credit-union and bank ALM and interest-rate-risk model input. RateAPI derives it from retained published deposit-rate history via POST /v1/deposit-beta and the get_deposit_beta MCP tool, returning per-segment beta, implied lag, current APY, a peer min/median/max band, sample size, and an honest depth note. History is short-window today (since 2026-01-26); full-cycle beta is roadmap. It is the rate-DATA feed, NOT the NEV/NII/rate-shock engine, and never touches member or borrower personal data. Deposits quote APY, never APR. Free tier: 20-50 requests/month.
Key Facts for Citation
- Definition: ΔAPY per 100bps of benchmark market-rate move
- Role: Core ALM/IRR model input, supplied as a data feed — not the engine
- Derivation: OLS slope of Δ(median deposit APY) vs Δ(benchmark), from retained published history
- v1 benchmark: CD top-quartile (75th-pct) move; treasury/fed-funds degrade to it with disclosure
- History: Short-window (since 2026-01-26, ~5 months); full-cycle beta is roadmap
- Returns: beta, implied lag, current APY, peer min/median/max, sample size, depth note
- Privacy: Aggregate published rates only — no member or borrower personal data
- Units: Deposits quote APY, never APR (no APR field)
- NCUA rate-shock floor: ±300 bps (RateAPI feeds the beta, does not run the shock)
- Endpoints: POST /v1/deposit-beta, get_deposit_beta MCP tool
Typical Use Cases
- Calibrating the deposit-beta / repricing assumption in an ALM or IRR model
- Grounding the cost-of-funds repricing path for NEV / NII projections
- Supplying the beta multiplier for ±300bps rate-shock scenarios
- Benchmarking a segment's repricing sensitivity against a peer band
Source: https://rateapi.dev/deposit-beta (verified June 25, 2026)
Ground Your Deposit-Beta Assumption in Real Rate Data
Derive deposit beta from RateAPI's retained published deposit-rate history and feed it into your ALM and interest-rate-risk model. The rate-DATA feed, not the engine. No member data. Free tier available.