> if Citadel is the prime broker for all of these shorts _significant_ exposure on that end, as well as the exposure that Citadel hedge fund has on the short position through Melvin.

Isn't this meant to be the reason for the "Chinese Wall"? In theory, Citadel as a brokerage is meant to have no insight into the operations or needs or desires of Citadel Hedge Fund. The technically correct answer here seems to be "not my problem", however... not so much.