There is no but, it will go to another registrar.
Edit: Let me explain. You dont really own your domain, it is more like a lease. You arent leasing it from the registrar, you are leasing it from the registry. When you purchase a domain for a year you give money to the registrar ( they are like an authorized dealer ), thye in turn give a portion of that to the registry ( the real holder of the rights to that TLD).
Take .com for example. I pay joes domain shack for ****. Joes then sends a portion of that to Verisign. If Joes goes out of business all of the information is already kept with Verisign. I dont know if it is bought or deligated to another registrar for sure but you will not be left in limbo.
Moving