Term Structure Extent
Table of Contents
Summary
A term structure is defined by its constituent tenor points, but nothing in that definition says how far the series extends before stopping — that extent is itself a convention, and it differs materially by curve type: interest rate curves stop at a fixed 30-year ceiling, volatility surfaces default to a much shorter 5 years while remaining able to quote out to 30, and CDS curves have no fixed ceiling at all, running instead to whatever the longest live trade in the portfolio happens to be. A term structure's behaviour for a request beyond its own last point is a second, related convention — flatten, not extrapolate — a deliberate, explicit choice rather than a failure mode.
Detail
Interest rate curves: a fixed 30-year ceiling
For interest rate (discount/projection) curves, the long end is
consistently 30Y — 15Y, 20Y, 25Y, 30Y are named together as the
standard long-end IRS pillars (see
Tenor's standard label table),
and the consensus-provider expiry list likewise terminates at 30 years.
Where a curve genuinely has no tenor beyond its last pillar, the system
does not silently fail a request past that point; it applies the
beyond-the-end convention below. If asked whether an interest rate curve
should extend to 30Y or 50Y, the answer is unambiguously 30Y — 50Y does
not appear as a curve length anywhere in the source material this cluster
draws on.
Volatility surfaces: a practical default, not a hard ceiling
For FX volatility surfaces, data normally extends only to 5Y, and that same 5Y point is conventionally reused as the surface's short-end/long-end curve split tenor for interpolation purposes. This is a practical default, not a structural limit: it must remain possible to view or quote a vol surface out to 30Y on request. Beyond the liquid ATM region, a common quoting convention applies a Zero Delta Straddle (delta-neutral straddle) out to 10Y, then an ATM Forward from 12Y through 30Y — a different quoting basis for the illiquid long end, not an extension of the same liquid-region convention.
CDS curves: open-ended, portfolio-driven
CDS/credit exposure has no fixed maximum tenor at all. Rather than a pillar-based ceiling, it runs "up to the longest maturity of the portfolio" — open-ended, and determined by whichever live trade happens to be longest, not by a fixed curve length the way IR and vol curves are.
Beyond the end: flatten, not extrapolate
What happens past 30Y (IR) / past 5Y (vol, if not quoting out further) / past the portfolio's longest CDS trade is governed by Extrapolation's general beyond-the-end policy: the system does not silently fail, and it does not default to extrapolation, which would manufacture a value with no basis — it holds the curve flat instead. See Extrapolation for the full policy, including the asymmetry with the before-the-start case, and Interpolation for how the region between known points is handled instead.
See also
- Term Structures and Tenors — the hub.
- Term Structure — the series this document states the extent of.
- Tenor — the standard long-end labels (15Y-30Y) that define the IR ceiling.
- Extrapolation — the general before-the-start/beyond-the-end policy this document's curve-type-specific ceilings feed into.
- Interpolation — the sister concept for values between known pillars.
- Pillar — what a pillar is, and how it differs from a tenor in general.
- Curve Point Provenance — how interpolated/extrapolated/flattened points are tracked and distinguished from directly-quoted ones.
- Interest Rate Curves — where these methods are applied to a concrete bootstrapped curve.
- FX Volatility Surface — the 5Y default extent and curve-split tenor in its native context.