When I first noticed yesterday that Fair Isaac Corp was unveiling a new credit score, I bookmarked the story as something to read later. But then the headline “eliminating piggybacking” caught my eye, and I read further.

Recently, a slew of companies have been created with the purpose of “sharing” good credit to people with bad credit. This works by having the person with bad credit signed on as an authorized user on a credit card from a person with good credit.

Obviously, this is not what this aspect of the credit score calculation was meant for. It was meant for spouses and children of people with good credit to give their loved ones a leg up when it came to establishing a good credit score. I benefited greatly from this from my dad, who didn’t have a single negative mark of credit in his life. By signing on as an authorized card user at 16, I was able to have a 750 credit score by the time I entered college. Not bad!

Unfortunately, some greedy people have tried to make money off of this system, so now the Fair Isaac Corporation has been forced to adjust the way the score is calculated. In September, their new system will, among other changes, basically eliminate the benefits currently garnered by authorized users.

So how do you share the benefit of your high credit score with this new system? First, you may still be able to start building a family member’s credit by signing them up as an authorized user immediately, but there’s no guarantee of how much of an effect that will have before the rules are changed in two months. The second option may be to instead sign them on as a joint user.

What is the difference between a join user versus an authorized user? Basically, a joint user shares in all aspects of the card – both good and bad. Specifically, if one user of the card racks up a huge balance and doesn’t pay, then both users are effected.

Since going on the internet and adding a stranger as a joint user would be a very risky endeavor, Fair Isaac has said that they currently plan to keep in places the rules regarding join accounts, meaning that you can still share your good credit. Just be sure you trust who you add as a joint user!