Reading spread when the UI says zero commission
Zero commission promotions still leave price impact — how we surface that line in scenario fee reports.
“Zero commission” is a venue statement about one line item. Liquidity spread is another. Clients who conflate them undervalue thin pools.
How we show both
On the Smart Crypto Calculator PC, commission and spread occupy separate rows. In a scenario fee report, we refuse to merge them into a single “cost” without a footnote. That footnote has stopped more than one client from picking the flashiest promo.
A mild reservation from our own practice
Estimating spread for very large sizes relative to pool depth is imperfect without venue-side depth that clients sometimes cannot share. When that happens, we mark the spread cell as a range and say so aloud. A false precise number is worse than an honest band.
Practice drill
Take a recent swap receipt. Cover the commission. Ask what else moved the effective price. If you cannot name it, run the pair again in a walkthrough or audit before the next size up.