Your shares and cash holding at held in custody at a custodian bank (ICBC US) on a books and record basis managed by DriveWealth. All your holdings and cash are registered in your name in a segregated account and are insured for up to $US500,000 under SIPC insurance. 

This is slightly different to the Australian system where each account has its own Holder Identification Number with the exchange clearing system (CHESS). In overseas markets, the custody arrangement is far more common.