It didn't come from anywhere.
From Bloomber:
>"FTX co-founder Sam Bankman-Fried’s $250 million bail package is one of the largest in US history, but it doesn’t mean he actually has to put up that kind of money.
At Bankman-Fried’s bail hearing on Thursday in federal court in Manhattan, both the prosecution and defense agreed that the former billionaire’s assets have “diminished significantly.” Bankman-Fried has said he may have only $100,000."[1]
>"The $250 million personal recognizance bond approved by the judge was secured by the equity in Bankman-Fried’s parents home in Palo Alto, California, which is almost certainly not worth anywhere near that amount. But outsized bonds are more a means of establishing harsh financial consequences for bail-jumping and are often backed by assets worth only around 10% of the stated amount."[1]
Further:
>"In addition to Bankman-Fried and his parents, the bond must be signed by two other people of “considerable means,” one of whom can’t be a relative, by Jan. 5"[1]
So it sounds like he able to leave today with nothing more than the equity in his parents house pledged and now has until the 5th of the new year to find the other non-family signatory as well as the rest of the funding. I've read in multiple sources that his parents house appraised somewhat recently at $4 million, so that max equity they could have would be that. So if they are required to put down 10% that still means they need to find another 21 million dollars somewhere.
[1] https://archive.vn/QeZy7#selection-4563.0-4563.157