*Loan,banking and credit>>>credit score

Increasing credit score?

If I add an aged trade line (i.e. added as an authorized user on my parent s CC), will that increase my score quickly? I know there are services that will do this for a fee, but I'm not talking about that. I'm just wondering if anyone has ever done this, if it worked for them, and how quickly it worked. Thanks.

You are talking about a process called "Piggybacking". The short answer is yes it will help. However, your parents have to have a PERFECT and long history with the account they add. If they have late payments or are close to their limit it could hurt your score by adding additional negative items. Also, if you have any major negative items such as Charge-Offs adding a positive account may help some, but it won't be a big boost.

However, this is only a short term benefit. The companies that are doing the scoring systems are going to stop including Authorized Users in scoring calculations in the next few months. Fair Issac who does the FICO Score is supposed to have the new scoring system in place by September.

OC is correct that in the short term becoming an authorized user to someone with excellent credit can help your credit score, but like the services you mentioned the practice has been abused to the point that starting in September of this year authorized users will no longer be considered in the scoring system.
credit analyst/underwriter
Yes, it does work. It will give you all the credit history they have. It goes on the report immediatly, but I have been told it should stay on ther for at least 3 months before obtain any new credit.

However, there are laws against doing this for any one other that a relitive. So just be careful.
Personal experiance