Sony has taken 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 are 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’ve 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.