---
title: "Treasury FRN daily index + projected coupon"
method: GET
path: "/api/v2/fixed-income/treasury/frn-index"
tags: ["Fixed Income"]
---

# Treasury FRN daily index + projected coupon

`GET /api/v2/fixed-income/treasury/frn-index`

US Treasury Floating Rate Note (FRN) daily index rate + projected current coupon: the 13-week-bill high-rate index, the auction-set spread, the projected coupon (index + spread), and accrued interest. Omit cusip for the latest across all FRNs, or filter by cusip. Source: US Treasury Fiscal Data (CC0).

## Query parameters

- `cusip` string, nullable — Filter to one FRN CUSIP.

## Response `200`

FRN daily index rows with projected coupon and accrued interest.

- EnvelopeFrnIndexData
  - `data` FrnIndexData, required — FRN daily index + projected coupon rows (latest first).
    - `count` integer, required
    - `rows` FrnIndexRow[], required
      - `record_date` string, nullable
      - `cusip` string, nullable
      - `frn` string, nullable
      - `maturity_date` string, nullable
      - `spread` number, nullable — Auction-set spread over the 13-week-bill index, percent.
      - `daily_index` number, nullable — 13-week-bill high-rate index, percent.
      - `projected_coupon` number, nullable — Projected current coupon (index + spread), percent.
      - `daily_accrued_per100` number, nullable
      - `accrued_per100_pmt_period` number, nullable — Accrued interest per 100 face this payment period.
  - `meta` SugraMeta, required — Metadata attached to every /api/v1/* response envelope.
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 UTC timestamp of the source data, not of the request.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.

## Other responses

- `401` — Missing or invalid `x-api-key` header. JSON body with a stable `code` distinguishing `missing_api_key` (no header sent) from `invalid_api_key` (header sent, key not accepted); any other 401 source carries the generic `unauthorized` with its detail as `reason`. Plus `hint`. `plan` is always null on 401 - an unauthenticated request has no plan; quota exhaustion is 429, not 401.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

---

[API](https://skmtc.net/sugra/apis/sugra-api.md) · [All operations](https://skmtc.net/sugra/apis/sugra-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/sugra/sugra-api/revisions/a83e6a561bf2/schema)