VIX Special Opening Quotation (SOQ)
VIX SOQ Value History
Here you can find full history of VIX settlement values (SOQ at expiration day):
Here you can find the SPX option series used for SOQ calculation (the options used for calculating VIX settlement value) on each VIX expiration:
There is an Excel file for download for each expiration. There is also “Likely VIX Series”, which is published on the last trading day (the day before the actual expiration).
What Is VIX SOQ?
VIX Special Opening Quotation (SOQ) is a special VIX value calculated at open on the final settlement (expiration) day of VIX options and futures. It is calculated from a series of S&P500 options – this is the same as the calculation of “normal” VIX values, but there are a few specifics in case of SOQ. Unlike “normal” VIX values, the SOQ uses prices which have actually been traded (not just the mid prices). The prices are determined in the Hybrid Opening System (HOSS). The mid (average of bid and ask) at open is used for options which don’t have a traded price (only options with non-zero bids are used).
VIX SOQ Official Explanation on CBOE.com
The procedure of the Hybrid Opening System (HOSS) and determining VIX SOQ on the expiration day is explained in detail on the official website of CBOE:
See also questions 6 and 7 in the official VIX FAQ by CBOE: