Slippage is the difference between the price you were quoted and the price your trade actually executes at. Prices move between the moment Mo builds a quote and the moment the transaction lands on Base. Usually the gap is tiny. Sometimes it isn’t.
Your slippage tolerance is the size of gap you are willing to accept. Mo defaults to 0.3%. If the executed price would be worse than that, the trade is rejected instead of filled.
Why the price moves at all
A quote is a snapshot. Between the snapshot and settlement, other people trade the same pool, the market price shifts, and the pool you are routing through changes shape. Thin liquidity makes this worse: a large order in a small pool moves the price by itself, which is why the same trade can be fine at $50 and expensive at $50,000.
Setting the tolerance
| Tolerance | What happens |
|---|---|
| Too low | The trade fails more often. Nothing moves, but you have to try again. |
| 0.3% (default) | Fills most orders on liquid assets without giving much away. |
| Too high | The trade almost always fills, and you can accept a noticeably worse price. |
A failed trade is not a lost trade. If the transaction is rejected, your assets are untouched and you can request a fresh quote at the current price.
The other reasons a trade fails
Slippage is the most common cause, but it isn’t the only one.
- The quote expired. Quotes are short-lived on purpose. Confirm promptly or get a new one.
- Not enough balance. You need the trade amount plus the network cost of the transaction, not just the amount.
- The asset isn’t available where you are. Coinbase Tokenized Stocks in particular are restricted to eligible non-US persons. See where Trade is available.
- A vendor outage. Orders route through OKX DEX, or through Coinbase’s stocks vendor when a tokenized stock is on either leg. If one is down, quotes stop.
What to do when it keeps failing
Try a smaller amount first. If a smaller order fills and a larger one doesn’t, the pool is too thin for the size you want, and splitting the trade usually costs less than raising your tolerance. If nothing fills at any size, the asset or the route is likely unavailable rather than illiquid, and support can tell you which.
Raise the tolerance only when you actually want the fill more than you want the price, and lower it again afterwards. A tolerance you set once during a volatile hour will quietly cost you on every calm trade after it.
Mo shows what you pay before you confirm: the vendor conversion cost, the network cost, and the Mo integration fee, which is 0.10% for Free members and 0% on Mo Plus. Slippage is the one number on that screen you control.