I sold a spread bet on the product "Volatility Index" which as far as I understand is designed to track the VIX. However, when I sold it, the VIX was at 36 and the "Volatility Index" was at 34 so VIX was 2 points higher. Now that VIX has fallen to 26.7, the Volatility Index is at 27.4, so VIX is now almost a full point lower. Note this is not a BID/OFFER issue, which trades about 0.3 wide.
This is also not a 'funding bleed' issue, because the position is costing me money to hold every day, so that cost is not built in.
Does anyone understand the construction of this Volatility Index, and why my trade has underperformed VIX?
Personally I feel quite mislead, as this product is clearly marketed to track VIX.
Grateful for any information.
thanks