In changes made to the formula figuring out your credit score, the FICO(Fair Isaac Company) will no longer consider authorized user accounts. This comes from what is called attempts to defraud lenders. This decision has come in response to the loophole that companies were taking advantage of until this change.
An example of this is Company A would pay Consumer A with excellent credit score, accounts, and history for the rights to put other consumers as authorized users on the accounts. Then Company A would charge Consumer B with poor credit accounts to be put on the good accounts as an authorized user. This would inflate the credit history showing great accounts on consumer B’s reports and raise the credit score.
Most authorized user accounts are held by family members or close personal friends. However because of these practices by the companies and since FICO can’t determine how the authorized user accounts are connected FICO has decided to no longer consider authorized accounts this coming fall. Here is more information on the MyFico Support Center.