> For the complete documentation index, see [llms.txt](https://docs.aspanfi.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aspanfi.com/core-concepts/the-dual-token-model.md).

# Native ASPAN DeFi

Native ASPAN DeFi is one of the two optional yield paths proposed for ASPAN Account. It retains the existing BNB collateral structure, while planned ASPAN Vaults would manage separate external strategies.

Account funding and payment authorization do not require participation in native DeFi. Selecting this strategy means accepting its collateral, token, and withdrawal risks. The existing source foundation does not establish a completed integration with the new account.

### The dual-token foundation

The core protocol divides collateral value into two risk tranches: apUSD and xBNB. Staking apUSD produces s-apUSD vault shares, rather than a new independent collateral tranche.

### apUSD: the dollar-denominated liability

apUSD is minted against supported BNB liquid staking collateral and designed to target $1. The target depends on collateral and protocol mechanics; it is not a guarantee of market price, principal protection, or immediate cash redemption.

Holding unstaked apUSD is distinct from holding yield-bearing shares. In the new account design, apUSD is an optional strategy asset rather than the required unit for all account deposits and payments.

### s-apUSD: shares in the native staking vault

Users stake apUSD in the Stability Pool and receive s-apUSD. Underlying staking income is allocated according to protocol rules and can increase the value represented by each share. Returns depend on income, fees, and protocol conditions.

The referenced vault has configurable withdrawal delays. During stability mode, redemption can return a mix of apUSD and xBNB. s-apUSD is not the share token for the separately planned external-strategy ASPAN Vaults.

### xBNB: the residual risk tranche

xBNB NAV = (Collateral value − apUSD liabilities) / xBNB supply

xBNB receives residual collateral upside and downside after apUSD liabilities. Its effective leverage changes with the balance sheet; it is not a fixed 3× product and can lose all value.

The structure does not use perpetual-style recurring funding payments or a holder-specific margin account. Mint and redemption fees, foregone staking income, liquidity, and protocol operations still affect results. The strategy depends on viable demand for the residual risk position as well as apUSD; concentrating staking income does not create new revenue.

### Selection within ASPAN Account

Native DeFi would be evaluated against the same owner-defined criteria as other strategies: underlying exposure, expected net return, concentration, withdrawal timing, and usable exit assets. Being an ASPAN product does not give it priority or justify relaxing a user's limits.

Before funds can pay a service bill, the required withdrawal and any conversion into the recipient's payment asset must complete. xBNB is not a stable payment reserve.

### Mechanics and security references

* [The Invariant](https://docs.aspanfi.com/core-concepts/the-invariant): native collateral accounting.
* [Stability Pool & Yield](https://docs.aspanfi.com/aspan-mechanics/stability-pool-and-yield): income, shares, and withdrawals.
* [Dynamic Fee](https://docs.aspanfi.com/aspan-mechanics/dynamic-fee): documented native DeFi fee bands.
* [Smart Contract Security](https://docs.aspanfi.com/risk-management/smart-contract-security): initial DeFi-only audit and its limits.