MIAX Options Exchange - Updates To The SPIKES Special Settlement Auction Settlement Reference Price Opening Width And SPIKES Valid And Priority Quote Width Tables Date 19/04/2021 Due to sustained market volatility, MIAX Options will continue to use the Settlement Reference Price Opening Width and Valid and Priority Quote Width tables detailed in MIAX Options Regulatory Circular 2021-04 for opening the SPY May 21, 2021 options used in the April 21, 2021 SPIKES Special Settlement Auction.