The word SAFU plays a homophone of "safe" and first appeared in 2018 by content creator Bizonacci in a goofy video posted on YouTube.

On March 7, 2018, users discovered that Binance had entered an unexpected maintenance period, resulting in the inability to log in to their accounts. The root cause of the maintenance was a malfunction in the SYS/BTC trading pair, which allowed hackers to exploit the security flaw. To reassure nervous users that their funds were not at risk, Binance CEO Changpeng Zhao tweeted "all funds are safe." Later, Bizonacci uploaded a silly video titled “Funds are Safu.” The video went viral and created the meme.

Later, Binance officials ended up playing tricks and established the Secure Asset Fund for Users (SAFU). In July 2018, Binance committed to donating 10% of all transaction fees to the SAFU fund to protect user funds. The funds are stored in a separate cold wallet. As of May 2023, the SAFU fund is worth two billion dollars.

The Safe Asset Fund for Users (SAFU) and this viral video (now removed) have made the word safu a common word in crypto slang. Changpeng Zhao later helped popularize the meme, using the hashtag #safu on multiple occasions and tweeting "Funding is SAFU" during follow-up maintenance on his crypto exchange.