Citadel’s space includes two of what Levinson calls the “diagrid” floors — the 14th floor mezzanine with 20-foot high ceilings that overlooks the 12th floor trading area with its ...

Citadel Securities has quietly become one of the largest forces in U.S. stock trading. From the 35th floor of a downtown Chicago office tower, Citadel executes one out of every eight stock trades ...

Citadel Securities went from strength to strength ... just posted record revenue -- some of it from a rapidly constructed Florida trading floor. Fourth-quarter net trading revenue of $1.7 billion ...

Inside Ken Griffin’s Citadel Securities, a new strategy for handling even more of Wall Street’s trading is starting to take shape — with implications for struggling banks and brokerages ...