A federal judge dismissed a case Monday that alleged the Chicago Board Options Exchange (CBOE) knowingly allowed anonymous traders to manipulate the option exchange market. The traders who filed the suit argued that CBOE violated the Securities Exchange Act and Commodity Exchange Act to increase profitability and acted negligently by allowing the manipulation.

CBOE founded the VIX, a published number that predicts the S&P 500 stock index volatility within 30 days. The VIX updates every 15 seconds and is determined by a specific formula. The traders brought suit alleging that other traders learned how to sell options strategically to manipulate that formula and profit from these manipulations.

The plaintiff traders alleged that CBOE knew of the manipulation and did not seek to rectify the error. Regardless, Judge Manish Shah of the Northern District of Illinois dismissed the case because CBOE did not know or collaborate with the manipulators:

Here, by contrast, plaintiffs do not plead that Cboe was a coparticipant in any manipulation. Cboe did not conspire with the Doe Defendants, develop its formula to assist the Does’ strategy of manipulation, or market any particular product exclusively to the Does, so Cboe’s relationship to the Does is not comparable to the Barclays defendants’ relationship with the HFT firms. Plaintiffs do not plausibly allege that Cboe knew who the Does were, let alone that Cboe worked with them to develop specific, exclusive products. Rather, plaintiffs allege that Cboe’s flawed design allowed anonymous third parties to manipulate the settlement process and Cboe failed to correct it.

Shah additionally reasoned that CBOE did not profit from the manipulation and that any person could have engaged in such manipulation. Likewise, Shah found that there was no way to determine whether the manipulation actually harmed the options of the traders who filed suit.