@useparity / Parity is a Uniswap v4 hook built for tokenized stocks on Robinhood Chain (chain 4663).

The problem is ugly and specific.

Robinhood stock tokens don’t change your balanceOf when a company pays a dividend or does a split. They bump a global uiMultiplier() instead. AMMs still price off raw balances. So the pool’s value jumps and the pool’s math never notices.

What happens next is textbook: an arb bot sees the misprice first and extracts it. LPs eat the loss.

• A small dividend on a $125k pool? Maybe a few dollars.

• A 4-for-1 split on the same pool? Their sim shows ~$124k extracted in one tx. Loss scales with the square of the multiplier jump.

Parity’s hook is the thing that notices.

It watches effectiveAt() (corporate actions are announced on-chain before they hit). In the pre-rebase window it:

• blocks JIT liquidity dumps

• surcharges the extracting swap direction

• pays that surcharge back to LPs

• then drops fees back to base once the “leak budget” is repaid

Tagline is accurate: the arb pays the LPs, not the bot.

They also have a $PARITY token on 4663:

• 1B fixed supply

• zero emissions

• not a claim on hook fees

• used as keeper bond collateral: miss an announced corporate-action window and you get slashed to the undefended LPs