Every P2P ad advertises a minimum and maximum trade size. It's tempting to treat that maximum as fact — it's printed right there on the ad. It isn't fact. It's a ceiling the merchant set once, and it routinely has nothing to do with what the ad can actually fill right now.
The field that actually matters
Binance's own API carries a separate field, dynamicMaxSingleTransAmount, that tracks real-time fillable capacity — not the advertised ceiling, the merchant's current tradable quantity multiplied by price. As a merchant's inventory depletes through partial fills, this number shrinks. The advertised maximum doesn't move at all.
A concrete case
On one CIH Bank rail, three ads were pricing the ask between 9.74 and 9.78 MAD while their dynamicMaxSingleTransAmount sat between 221 and 432 MAD — nowhere near enough to fill a 500 MAD order someone might reasonably try to place against the advertised price. Despite the field's name suggesting an asset-denominated quantity, it's fiat: tradable quantity times price, which is why it compares directly against a trade size specified in MAD rather than needing a separate conversion.
Why this is easy to get wrong
Nothing about the ad's headline presentation flags the gap. The advertised min/max looks identical whether the merchant has full capacity or is nearly exhausted — you only see the difference by reading a field most P2P tools don't surface at all, and definitely don't filter on.
How we verified it
This isn't a one-off reading. It was checked across 5 payment rails and 3 trade sizes against Binance's own server-side payTypes and transAmount filters — 17 of 17 cells agreed within one price tick. When we say a price on this site is fillable at a given size, it's checked against this field, not the advertised ceiling.
What this means for you
- An ad's top price being attractive says nothing about whether your specific trade size can clear it.
- Public P2P price pages that show only advertised min/max — which is most of them — can point you at a rail that looks open and isn't.
- If a tool doesn't mention correcting for real-time fillable capacity, assume it hasn't, and size your first fill smaller than you'd otherwise plan.