Just a tracker. All they have is the name of the crypto and how many shares and what price you paid for it if you know and the date you bought if you know that. Very helpful. They dont even know where you have the crypto at so no way they can have access to your tokens. One thing I have found out is that security is very big at all the exchanges. I am constintly having to put in codes from my cell phone and my email on all the exchanges. I can see how it would be very hard for anyone to hack them.