Most of the time, the only way the number of tokens in your wallet changes is that you send or receive one. You sign a transaction, it lands on chain, and your balance updates because something actually moved. Rebase tokens break that assumption. Their supply expands or contracts on a schedule, and every holder's balance shifts along with it, without a transfer ever happening. If you have ever opened a wallet and seen a token balance that is different from the last time you checked, with no transaction to explain it, this is usually why.
What "rebase" actually means
A rebase, or elastic supply, token is programmed so its smart contract can change the total number of tokens in existence. When that happens, every wallet's balance is adjusted by the same proportion. If the supply grows by 2 percent, your balance grows by 2 percent too, and so does everyone else's. Your share of the total supply stays exactly the same. Only the absolute number displayed in your wallet moves.
This is a different mechanism from a token simply going up or down in price. Price reflects what the market will pay for a token. A rebase changes how many tokens exist in the first place. A project can rebase and have the price stay flat, because the two numbers (supply and price) are adjusting to offset each other by design.
A concrete example
Ampleforth (AMPL) is the token most often used to explain this mechanism, because rebasing is its entire premise. It targets roughly one dollar per token, and once a day its contract compares the market price to that target. If AMPL is trading above target, the contract expands supply, and every holder's balance goes up. If it is trading below target, supply contracts, and balances go down. No one sends or receives anything for this to happen. It is a global adjustment applied by the contract itself.
Liquid staking is where most people encounter a rebase token without realizing it. Lido's stETH, which represents staked ETH, increases in balance over time to reflect staking rewards, again with no transfer event showing up in your history. Lido also offers a second version, wstETH, which works the opposite way: your token count never changes, but each wstETH becomes redeemable for a growing amount of ETH over time. Same underlying rewards, two different ways of representing them. One rebases, the other does not.
OlympusDAO's staked token, sOHM, rebased roughly every eight hours during its rebasing era, with balances increasing based on the protocol's stated yield. It is worth noting that sOHM was designed mainly to be held or unstaked rather than freely traded, which set it apart from a token like AMPL that circulates and trades directly while rebasing.
Why rebase tokens cause friction in DeFi
The core problem is that a lot of DeFi infrastructure assumes your balance only changes when you initiate a transaction. Automated market makers, the pools behind most decentralized exchanges, generally were not built with the idea that a pooled token's supply might shift on its own. Some DEXs handle rebasing tokens awkwardly or not at all, which is a large part of why wrapped, non-rebasing versions like wstETH exist. Wrapping converts a rebasing balance into a fixed token count with a floating redemption value, which plugs cleanly into lending markets, liquidity pools, and anywhere else a stable balance is expected.
Lending markets have a related issue. If a rebasing token is posted as collateral, a positive rebase would need to be split fairly between the borrower and the protocol, and a negative rebase raises the question of who absorbs the loss. Most lending protocols simply avoid accepting rebasing tokens directly for this reason, favoring wrapped versions instead.
The tracking and tax problem
Because a rebase does not produce a normal on-chain transaction, it will not show up as a labeled event in a block explorer the way a transfer does. If you are trying to reconstruct your holdings over time, or figure out exactly when a balance changed and by how much, a rebasing token can be genuinely hard to audit after the fact. Tax treatment is also unsettled in many jurisdictions. It is not always clear whether a rebase increase counts as income when it happens or only when you eventually sell. This is a real gray area, not a case where there is a clean, universal answer, so treat it as a question for a tax professional rather than something to assume either way.
What to check before holding one
If you come across a token that describes itself as rebasing, elastic supply, or auto compounding in a way that changes your balance directly, it is worth confirming a few things before you hold it: whether the project has a wrapped, non-rebasing version for use in DeFi, whether the exchange or pool you plan to use actually supports rebasing balances, and whether your own recordkeeping can handle balance changes that are not backed by a normal transaction. None of this makes a rebase token inherently unsafe. It is simply a different mechanism from the fixed-supply tokens most people are used to, and it is worth understanding the difference before your balance moves on its own.