Ascnt Vault

USDa is a yield-bearing stablecoin vault. You deposit USDC and receive USDa, an ERC-20 share token. The vault supplies the deposited capital as concentrated USDC/USDT liquidity on Uniswap v4; the trading fees it earns accrue to the share price, so USDa appreciates against USDC over time with no claiming or compounding step. It's an ERC-4626 vault internally (OpenZeppelin v5), but the standard mint/redeem entrypoints are disabled in favor of custom deposit/withdraw functions.

How it works:

Adaptive positioning. The vault reads a companion Uniswap v4 hook that records where swaps land and returns the tick ranges covering 90% / 99% / 99.9% of trading volume. The vault holds four positions: a thin full-range backstop plus three positions placed in those hook-reported bands, so most capital sits where most fees are generated.

Self-rebalancing. A best-effort rebalance runs at the end of every deposit and withdrawal (and can also be triggered permissionlessly), moving the hook-driven positions as the market drifts. No keeper or off-chain bot is required.

Donation-proof NAV. Net asset value is computed from position liquidity, uncollected fees, and internally tracked idle balances only — never from token.balanceOf. Sending tokens directly to the contract therefore cannot move the share price, which closes the standard ERC-4626 inflation/donation attack.

Oracle-free pricing with a peg clamp. Prices come from the pool's own sqrtPriceX96, not an external oracle. For valuation, that price is clamped into a configurable peg band, so an in-block price manipulation cannot inflate or deflate NAV to mint shares cheaply or redeem them richly. Deposits are also rejected when the pool is off peg.

Off-pool swaps. When the vault needs to rebalance token ratios, it never swaps in its own pool (which would move the price it values itself against). It routes through a separate deep pool with a backup router, behind a two-sided balance check that bounds any swap to "spent ≤ in, received ≥ out" — a bad quote can only fail, not cause a loss.

Pro-rata fee accounting on exit. A Uniswap position settles 100% of its accrued fees on any liquidity decrease; the vault withdrawal path detects this and pays each user only their proportional share of principal and fees, retaining the remainder for other holders.

Dual-token exit. Withdrawals can be taken in USDC or USDT. If USDT depegs, a user can redeem in USDT rather than realize a loss converting to USDC; the same peg-band logic that guards NAV also gates this path.

The codebase includes the vault contract, the distribution hook, a unit/fork test suite, and an adversarial security review (AUDIT.md) that found and fixed two critical issues (fee over-collection on withdrawal and spot-price NAV manipulation) plus several lower-severity items.

This project is built on top of the uniswap v4 hooks architecture, which was required in order to pull swap by swap data without any off chain calls/oracles. The project consists of two main contracts, the v4 hook contract which acts as a sudo-oracle, tracking swap data, and exposing a function which calculates the historical price distributions mentioned previously. Then, each time a vault user interacts with the vault to either mint or burn their vault deposit (in the form of an erc4626), we use their transaction to call the hook function, calculate distributions, and reposition the vault. Due to the v4 architecture, we are able to do all this for relatively normal gas costs to the depositing/withdrawing user.