The Secure Asset Fund for Users (SAFU) is an emergency insurance fund that was established by Binance in July 2018 to protect users' funds. When the fund was established, Binance committed a percentage of trading fees in order to grow it to a sizable level to safeguard users.
The origin of SAFU
During unscheduled maintenance, Changpeng Zhou (CZ), the Binance CEO, tweeted out to users stating:
Funds are safe
After this, the phrase "Funds are safe" became regularly used by CZ to ensure users were aware that their funds were, in fact, safe.