I don't know what is widely assumed, but I personally assume it was one of the insiders who shared credentials with the pretty clear intention of making it impossible to individually attribute any shenanigans, most likely SBF himself who actually did the theft.
Given the degree of surveillance he is under, he probably didn't directly execute the sale (but I wouldn't bet too heavily even on that.)
i would guess about 0% likelihood it is him. more liekly a hacker or employee. Being CEO, Sam would have the authority to take the money himself. He would not need to hack his own exchange.
We're a talking private company in the Bahamas that has no oversight. There are no shareholders, board of directors, or audits. Sam can just go to the databases of pooled funds addresses from his admin panel and move some of those funds from A to B. Assuming anyone notices, he can pretend to be clueless. That is the scary thing about exchanges and why so many people in crypto say to self-custody. Your money is in the hands of people who can do whatever they want with it.
Didn't at least one major theft occur just as Altman was forced out as CEO?
And, in any case, avoiding attribution would be important whether or not he was CEO and especially if done when FTX was still pretending to be a viable business, since embezzlement isn’t legal and the CEO running off with a bunch of corporate assets kind of kills trust in the business.
Given the degree of surveillance he is under, he probably didn't directly execute the sale (but I wouldn't bet too heavily even on that.)