A chinese big investor has been victim of SIM hacking and this made possible for an attacker to access to bitcoin deposits of this user and steal cryptocurrencies (BTC and BCH) for around 45$ millions worth.
Around $30 million worth of BCH (100,000 coins) and $15 million worth of Bitcoin (1,550 coins) were stolen.
What is a sim hack? This is an attack for violate the 2FA authentication based on a sms smartphone send. This is infact very insecure and it is always strongly recommended to use only 2FA based on hardware keys like for example yubikey or equivalent. Be very careful, you see what can happen.