Quote from arturo3:
OK. The story is this one. I made it simpler, but apparently didn't wotk.
I bought CALL 11500 on DJI sold by goldman sachs on the italian market. They are called "covered warrants" and are sold only on the italian market. However, they told me will that they will refer to the CBOE price for the reimbursement. Since this price is apparently not reported, probably they meant the DJX and not DJI. They might also have used those options, i mean the DJX ones, to hedge their position and for this reason they need to refer to its price.