I've studied along guys/gals who've done IMO, also had them as co-workers at other times, they have never performed well.
I really like Linus' saying "talk is cheap, show me the code". These people can make a thousand arguments about why something should/shouldn't work (but never write code), then you show up with working code and they don't have much else to say.
How does it reflect poorly on Jane Street? These are people who left, after not very long.
If your thesis is "they were inexperienced and operating without sufficient supervision" then that's a big part of what the structure of a place like Jane Street gets you.
I think it means Jane Street likely hires with a lot of bias for elites and “twitchy” smart people. The CEO of Alameda was an intern there and invited back for a full time position. Hearing her speak in interviews makes it seem like she has no idea what she’s doing and not all that intelligent or thoughtful. So it’s weird that she, seemingly easily given she states in interviews that she had no trading experience prior to Jane Street, made it through their supposedly rigorous hiring process. It seems their hiring process may not be as rigorous or effective as they hoped, which seems obvious even looking at the process in a vacuum.
Most probably. Web searching for that Caroline Ellison young lady I found some articles describing her as a young math prodigy when she was in highschool (or something like that).
They like to give the impression they hire Ultra Mega Geniuses who have done the IMO (who cares if you did the IMO at age 17...?)