> For the complete documentation index, see [llms.txt](https://docs.kuma.bond/kuma-protocol/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.kuma.bond/kuma-protocol/developers/smart-contract-architecture/rate-feed.md).

# Rate Feed

The upper bound for a `KIBT` rate of a risk category is the central bank rate coupon of the most recently issued bond for the risk category. This central bank rate is served on-chain by the `RateFeed` contract. Each central bank rate is given in terms of the per-second coupon, matching the format used in the `coupon` property in `KUMABondNFTs` . The `RateFeed` queries oracles, referenced as `MCAGAggregator` contracts, that follow Chainlink's `AggregatorV3Interface` for the rate data. Each `MCAGAggregator` serves the most recent coupon data for each risk category, and is managed by `MCAG`.