# RatchetFloor

> A price floor that only ever moves up.

A production Uniswap v4 hook. Source: https://github.com/nirholas/ratchet-floor. Part of the HookForge catalogue: https://hookforge.pages.dev

## How it works
A token's floor price is normally a promise: a treasury that says it will bid, a team that says it will buy back. Promises are only as good as the balance behind them and the people holding the keys. This hook makes the floor a property of the pool instead. It records the highest tick the pool has ever reached and refuses to let the price settle more than `offsetTicks` below it:   floor = max(floor, highWaterTick - offsetTicks) The floor is monotone by construction. It has no setter, no owner and no emergency path, so it cannot be lowered by anyone, including whoever deployed the pool. A rally raises it permanently; a decline never moves it. How a swap meets the floor matters, so it is worth being precise. Uniswap v4 swaps already take a `sqrtPriceLimitX96`, and {sqrtPriceFloorX96} returns exactly the value to pass: a swap carrying it fills as much as the floor allows and stops there, which is the behaviour a seller wants. The `afterSwap` check is the backstop for callers that pass no limit, and for those the swap reverts rather than partially filling. Routers should read the floor; the revert exists so that a router which does not cannot break the invariant. One tick is one basis point to within rounding, so `offsetTicks = 2000` is a floor twenty percent below the high.

## Prior art
Floor prices are usually a treasury commitment (protocol-owned liquidity, OHM-style backing) or a buyback hook that spends fees defending a level. Both depend on a balance and on whoever can move it. Enforcing a monotone floor as an invariant of the pool, with no treasury and no key, is a different construction: nothing is spent defending it and nothing can lower it.

## Where it does not help
This guarantees the pool will not print below the floor. It does not guarantee anyone can sell at the floor, because it holds no capital: once the price reaches the floor there is simply no more selling into the pool, and a holder who wants out has to wait for the price to recover or trade elsewhere. It converts a liquidity risk into a liquidity halt, honestly and predictably, but it does not make the risk disappear. A pool that needs a real bid at the floor needs a treasury behind it, and this is not that.

## Facts
Slug: ratchet-floor
Contract: RatchetFloorHook
Callbacks: afterSwap, afterInitialize
Parameters: offsetTicks (uint24)
Dynamic fee required: no

## Caveats
- Unaudited.
- A deployment with status "deterministic" is a mined CREATE2 address with no code at it yet. Never present one as live.