The SEC says the VIX index published stale values during the market spike on Feb. 5, causing huge losses on a Credit Suisse futures contract.
A federal judge says investors failed to show the exchange intentionally designed a settlement process that made its VIX index vulnerable to manipulation.
Akuna Securities allegedly submitted improper trades to influence the final settlement value of the CBOE's measure of stock market volatility.
In a split second on Monday, one of the largest trades ever in options tied to the CBOE volatility index took place.
