M1 is a regulated financial institution. This platform is a registered broker/dealer with FINRA and a member of SIPC: 

M1 is a member of SIPC (Securities Investor Protection Corporation). SIPC protects against the loss of cash and securities held by a customer. SIPC protection is up to $500,000 which includes a $250,000 limit for cash. SIPC does not protect you for any decline in the value of your securities.  

M1 Spend and M1 Plus accounts are further insured through Lincoln Savings Bank.