Not something you have to prove when alleging spoofing.
However, Merck is one of Citadel’s investment arm’s largest holdings.
This may come as a surprise, but BP do better financially if they buy brilliant small companies on the cheap after the small brilliant companies have their market cap beaten to a fricking pulp.
This may also come as a surprise, but Citadel profits from companies that also own BP. Many of those companies want small brilliant company market caps beaten to a fricking pulp.
This may also come as a surprise, but large hedge fund/brokerages/market makers have high incentive to break firewalls and little worry about regulators enforcing disabled firewalls. Wet noodle wrist slaps.