I take it that you can still trade anything but USD on Monday right? But if your account is based in USD, then you can't trade? Also, Sunday will be trading as usual even for USD, despite the pending holiday on Monday?
ES futures will be open sunday night as usual and so will FX presumably- i know it does on IB where i trade
If your broker is open (and they should be), the market is too. FX trades sun night thru Friday, every week. Volume will just be lower on holidays as some US banks will be closed.
Well IB posted Sept 1 as a holiday for USD. But you're saying that doesn't mean there is no dollar trading, just that it's slightly thinner?
Thats right. Banks/Funds/Institutions still have overnight departments to manage their positions. Dollars aren't owned by the US Government and therefore cannot impose trading "holidays" on the dollar. US Institutions may not operate on a Statutory holiday (Even though many trading departments will still be open), yet dollar holders around the world (UK, Asia etc), can still buy and sell their dollars freely without US participation. Hence the FX market will still be "open".