I need to open a tenant security account.

I would like to use it to collect payments and track bank transactions but I am concerned about security. 

I feel the main reason the bank pays back taxes is to protect themselves of a tax foreclosure happening and they loose their security for the loan. 

Eventually, someone looks at the Move Out Documentation and decides the fate of a security deposit (again, with significant legal consequences) ...

"Also, if a person can demonstrate sufficient education or job experience showing his professional knowledge of unregistered securities, he too can qualify to be considered an accredited investor."

And the bank will need a contact person for security reasons.  

Secure funding for your flip through options like hard money loans, private investors, or leveraging your home's equity with a HELOC.

Over 10 is when you need to do a security offering of some type.

My question is can I legally keep their security deposit?

An umbrella policy is relatively cheap and I feel secure in doing it this way.