defi-research

I find CoW Swap's "Order Surplus" concept pretty misleading—maybe even deceptive.

When calculating "surplus," CoW Swap compares the final trade execution against the limit price—which is just the minimum amount you're willing to accept (quoted amount * (1 - slippage tolerance)).

Example: you're quoted 10,000 USDC for selling 1 token A, with a 0.5% slippage tolerance. Your minimum buy amount becomes 9,950 USDC. If the trade executes at 9,975 USDC, CoW Swap claims you got a 25 USDC "surplus".

But in reality, you received 25 USDC less than what you were quoted. That's not a win—it's just better than the worst-case fallback. Calling that a "surplus" feels like spin.

Software Engineer @megaphone-hq

Prev: @0xproject

Yeah, also users who don’t know think they are getting a “surplus” when a lot of times they may be getting less than the displayed number that they saw on UI. 😅

yeah, last big trade i made I had this exact issue. i did set the slippage low, but i was surprised when the quoted price -> the minimum received on the page

bad UI mostly? creates the bad UX

Yeah, this is deception and gaslighting

Pretty simple change on their side imo - just track the amount that was shown to the users

I get why it was done to save scope (simpler to impl), but this is a disturbing sleight of hand