The S.E.C. said the world’s largest cryptocurrency exchange mixed billions of dollars in customer funds and secretly sent them to a separate company controlled by Binance’s founder, Changpeng Zhao.

Bitcoin mines cash in on electricity — by devouring it, selling it, even turning it off — and they cause immense pollution. In many cases, the public pays a price.

Researchers documented $515 million in suspicious transfers from the cryptocurrency exchange.

SBF said in an interview that he had expanded too fast and failed to see warning signs.