What is a Rebase Token?
How it works
A rebase token's contract does not store your balance as a fixed number. It records an internal share count (Ampleforth calls these "gons") and computes your visible balance as shares multiplied by a global scaling factor. A rebase is one transaction that updates that scalar, instantly rescaling every wallet's balance in the same proportion — no per-holder transfers, no per-holder gas.
Two designs dominate. Price-targeting rebases read an oracle: if AMPL trades above its target (a 2019 CPI-adjusted dollar), the daily rebase expands supply so every holder receives more tokens, pushing the per-token price back down; below target, supply contracts and balances shrink. Yield rebases distribute rewards instead: stETH balances tick up daily as Ethereum staking rewards accrue, aToken balances grow with lending interest, and OlympusDAO's staked OHM rebased roughly every eight hours to pay staking emissions.
Because everyone is scaled equally, a rebase is economically closer to a stock split than a dividend — it never changes your ownership share by itself. And because balances change without Transfer events, naive integrations break: a Uniswap v2 pool does not observe a rebase, so supply changes inside the pool get skimmed by arbitrageurs rather than credited to LPs. Wrapped, non-rebasing versions (wstETH, wAMPL) hold the share count constant and let the exchange rate float, restoring composability.
Why it matters
Rebasing decouples "number of tokens" from "value," and misreading that gap has cost retail holders real money. OlympusDAO's quoted four-digit staking APYs in 2021 were mostly supply expansion shared pro rata — a bigger balance of a proportionally diluted token, not profit. Negative rebases cut the other way: when price falls below target, holders lose on price and balance simultaneously. Rebases also complicate everything downstream — AMM pools, lending collateral, tax accounting, and market-cap dashboards all need special handling or wrapped versions. If a protocol advertises extreme APY paid in its own rebasing token, understanding this mechanic is the difference between evaluating yield and mistaking dilution for income.
Real-world examples
Ampleforth (AMPL), launched in 2019, is the canonical price-targeting rebase token. In July 2020 its Geyser liquidity incentives drove demand, and daily positive rebases expanded supply until market cap peaked near $700M. When demand reversed, AMPL fell below its ~$1 target and entered consecutive negative rebases: holders watched both the price and their token balances shrink day after day, and market cap collapsed roughly 80% within two weeks — the classic demonstration that supply elasticity does not stabilize the value of a holder's position.
FAQ
Is a rebase token a stablecoin?
No. A price-targeting rebase token like AMPL steers its per-token price toward a target by changing supply, but the value of your holding still floats with market cap. A stablecoin holder keeps a stable balance and stable value; a rebase holder can hold a $1.00-priced token while their balance — and total position value — shrinks.
Does a rebase change my share of the total supply?
No. Every balance is scaled by the same factor, so your percentage of supply is unchanged — like a stock split. A positive rebase alone doesn't make you richer, and a negative one doesn't dilute you relative to other holders; changes in position value come from market price, not the rebase itself.
Why do rebasing tokens cause problems in DeFi protocols?
Balances change without any Transfer event, so contracts that cache balances — AMM pools, lending markets, vaults — fall out of sync. In Uniswap v2, rebase-created tokens in a pool can be skimmed by arbitrageurs instead of accruing to LPs. Wrapped non-rebasing versions like wstETH and wAMPL keep balances static and move the yield into an exchange rate instead.
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