By sponsor you mean the holder? I'm referring to the "currency shares" ETF's i.e. FXY, FXB, FCX, FXE, etc.
For example, look at the FXY, the Yen out in Jan 2014, a pretty illiquid month. The Jan 80 and 90 strikes which probably have a big spread trade on, have open interest of 14k and 23k...