Sony has took to their blog to announce that as of today, PlayStation Network users with sub accounts can upgrade to master accounts and transfer over their profiles.
Instructions on how to start this process is as follows:
►Login to your account at https://account.sonyentertainmentnetwork.com/. You will receive a message advising you can upgrade your Sub Account.
►Click “Upgrade Your Account” to get started.
►When you are ready to upgrade click, “Continue.”
►Congratulations, you have now upgraded your Sub Account to a Master Account.
Once you’re upgraded to a master account, you’ll be able to access the full feature set of PlayStation’s online experience, including PlayStation Store. Your profile will also be carried over when upgrading to a master account, along with items like your friends list and Trophies.