# USK

The USK is a KUMA interest-bearing token backed by [KUMA NFTs](https://docs.kuma.bond/kuma-protocol/kuma-protocol/regulated-nfts), themselves backed by US 12 months T-Bills. The USK is currently deployed on Ethereum, Polygon PoS, Linea and Mantle with a SellBondFee (via the ‘sellBond’ fees function) set at 0.01%. Contract addresses can be found [here](https://docs.kuma.bond/kuma-protocol/developers/contract-addresses).

**Approved KUMA NFTs Risk Category:**

* Currency: USD
* Issuer: US
* Term: 12 (months)

## Wrapped USK (wUSK)

The majority of DeFi protocols do not support rebase tokens. To overcome this problem and enable optimal USK composability, a wUSK token following the erc-4626 standard has been deployed (contract addresses [here](https://docs.kuma.bond/kuma-protocol/developers/contract-addresses)). More informations on the differences between USK and wUSK are available [here](https://docs.kuma.bond/kuma-protocol/kuma-protocol/defi-integrations).