Are you sure you're looking at actual USD exchanges as opposed to alt exchanges using USD as a measurement?
I'm verified on there but there's no way I'll ever use them again because of their bullshit nosiness. There are also properly regulated alternatives in certain jurisdictions and people do love a bit of margin. They really need to up their game.
No, I checked their rank on the coinmarketcap page for Bitcoin volume, but it converts all currencies to USD to facilitate comparisons. Bitstamp moved down to 15th place since I posted the OP, but that includes GBP,
EUR, JPY, and an HKD market. Without those markets Bitstamp's down to 8th place from number one.