Curves and Indicative Swaps

These datasets describe sterling term structures at a dated snapshot. They do not provide executable quotes. Rates are percentages, and each node's maturity or term appears in series[].dimensions.

Common Curve Request

http

GET /v1/rates/series?dataset=ois_spot_curve
GET /v1/rates/series?dataset=ois_spot_curve&tenor_months=60&from=2026-09-14&to=2026-09-14

All curve datasets in the next table require only dataset. tenor_months optionally selects one stored maturity; omit it for all retained nodes. They also accept the common date, metric, release and pagination parameters. Metric: rate_pct; unit: percent; basis: indicative.

Dataset	Product	What it represents	Important distinction
`ois_spot_curve`	Sterling OIS Spot Curve	Fitted zero-coupon sterling overnight-indexed reference rates across maturities.	A zero-coupon rate is not the par fixed coupon of an ordinary swap.
`ois_forward_curve`	Sterling OIS Instantaneous Forward Curve	The instantaneous forward-rate structure implied by the fitted OIS curve.	Not an observed future overnight rate or a fixed rate over a multi-year forward interval.
`nominal_gilt_spot_curve`	Nominal Gilt Spot Curve	Fitted nominal government zero-coupon yields.	Not yields to maturity on particular coupon-bearing gilts.
`nominal_gilt_forward_curve`	Nominal Gilt Instantaneous Forward Curve	Instantaneous nominal government forward yields.	Not the same instrument or economic basis as an OIS forward.
`real_gilt_spot_curve`	Real Gilt Spot Curve	Fitted real zero-coupon yields from inflation-linked gilt evidence.	Not nominal returns or a guarantee of an investor's realised purchasing-power return.
`real_gilt_forward_curve`	Real Gilt Instantaneous Forward Curve	Instantaneous real government forward yields.	Negative values can be economically meaningful.
`market_implied_inflation`	Market-Implied Inflation	Spot inflation compensation inferred from the gilt market.	Not observed CPI/RPI or an unbiased inflation forecast.
`market_implied_inflation_forward`	Market-Implied Inflation Forward Curve	Instantaneous forward inflation compensation.	Not a forecast of the inflation rate in a particular future calendar month.

Example requests for each additional curve:

http

GET /v1/rates/series?dataset=ois_forward_curve
GET /v1/rates/series?dataset=nominal_gilt_spot_curve
GET /v1/rates/series?dataset=nominal_gilt_forward_curve
GET /v1/rates/series?dataset=real_gilt_spot_curve
GET /v1/rates/series?dataset=real_gilt_forward_curve
GET /v1/rates/series?dataset=market_implied_inflation
GET /v1/rates/series?dataset=market_implied_inflation_forward

Maturity Availability

Use /coverage to inspect stored maturities and their available dates. Each curve family can support a different maturity range and historical range. The API validates that a requested node exists somewhere in the selected release; it does not calculate a new node for you.

For example, tenor_months=60 means five years, not observation month 60. A 61-month node is not guaranteed merely because 60 and 72 months exist. Do not infer a uniform grid or extrapolate beyond retained maturities and call those values API observations.

With no date filters, one latest product snapshot is selected before the maturity filter. If the chosen node is absent at that snapshot, the API does not fall back to an older date. To inspect its past observations, request a historical range explicitly.

Indicative Sterling Swap Rates

Dataset: indicative_swap_rates. Required: dataset. Optional term_years: 1, 2, 3, 5, 7, 10, 15, 20 or 25. Omit the term for all available supported terms.

http

GET /v1/rates/series?dataset=indicative_swap_rates&term_years=5

Metric: rate_pct, unit percent, basis indicative. This is a curve-derived par-equivalent fixed rate rather than a raw OIS zero-coupon node. The output identifies the term and rate conventions, including annual_fixed_leg_par_equivalent where applicable.

These values are analytical references, not bid/offer quotes. They may differ from dealer swap quotes because the instrument conventions, timestamps and source basis can differ. Do not represent them as tradeable prices, clearing prices or guaranteed refinancing rates.

Indicative Forward-Starting Swap Rates

Dataset: forward_starting_swap_rates. Required: dataset. Optional term_years: 2, 3, 5 or 10. Optional horizon bounds: integers 0-120, inclusive.

http

GET /v1/rates/series?dataset=forward_starting_swap_rates&term_years=5&horizon_from_month=24&horizon_to_month=24

This selects an indicative five-year fixed-rate interval starting 24 months after the chosen snapshot. The interval ends at month 84. term_years describes duration after the start, not the total time from today to the interval end.

Metric: rate_pct, unit percent, basis indicative. Series dimensions identify term and horizon_month. Observation metadata supplies the actual start/end dates and months. Omitting terms and horizons returns the available supported surface, subject to pagination.

Forward-starting rates are implied by the snapshot's curve. They are not forecasts of the executable quote that will actually be available when the start date arrives.

Interpreting Inflation Compensation

Market-implied inflation includes pricing effects such as risk and liquidity compensation. Inflation-linked instruments also have specific indexation conventions. Do not label this product as an official CPI projection, use it as an exact contractual lease-index substitute, or subtract it mechanically from an unrelated nominal instrument without considering conventions.

Dates and Conventions

Curve filters use YYYY-MM-DD. A range requests multiple retained snapshots, not an average curve over that range. Within each node series, observations are dated snapshots. Scenarios and one-month SONIA forward intervals are documented separately in Financing Scenarios.

Preserve returned compounding, day_count and interval fields rather than assuming all curves use the same convention. Frequency daily means a series of dated curve snapshots, not an intraday tick feed or a promise of a snapshot on every day.