Many consumers consider the credit agencies as dark, cryptic institutions. In a way, they are, but understanding how they work and who they really are can be helpful in maintaining a solid credit history — whetheryou want to get credit card offers or if you just needto borrow money.  Being vigilant about taking care of your credit history is the cornerstone of success.

In analyzing the major credit bureaus, any legitimate conversation starts with the “Big 3”: Experian, Equifax, and Transunion. We’ve included the contact information for each separate bureau, in case you have to work directly with one for a credit mishap or getting a line of credit. Remember, if you want to get a new credit card, borrow money or otherwise open a line of credit, you’re going to need to go through at least one of these ratings bureaus.

TransUnion

The third-largest credit bureau service in the U.S, Transunion is based in Chicago, Illinois and has 250 offices. While the agency does offer credit ratings to consumers, it’s probably bette to use one of the larger agencies such as Experian or Equifax if you need to run your personal credit. As an alternative, since they are a smaller agency, Transunion provides deals to smaller lending institutions such as credit unions for checking credit. It’s smart to keep that in mind if you plan on seeking some sort of credit through these companies if you consider utilizing TransUnion’s reporting system rather than the other 2 large agencies.

Equifax

Equifax is the second-biggest credit reporting institution in the United States. Though they are not the largest, they are the oldest and have records on over four hundred million people. Based in Atlanta, GA there appears to be some overlap with Equifax and Experian, with huge financial institutions such as Capital One checking both Equifax’s data as well as Experian’s when looking at a consumer’s creditworthiness.

Experian

Experian is the biggest credit agency around the world. Their corporate home base is based in Dublin, Ireland but they also have a big U.S. presence in Costa Mesa, CA. Because of their stature in the credit reporting community , it’s likely that Experian has a file on you if you have any credit history whatsoever. They also have huge B2B credit reporting operation, so if you ever want to borrow money to start your own company, it’s probably a good idea to have a good history with them.

The Best Way to Monitor Credit

While it is beneficial to work with individual credit agencies to make sure your potential to borrow is sound, you may want to think about getting a “Triple Alert” service. Alternatively, when you get your free credit report (you qualify for one from these bureaus once every 12 months) make sure that it has all of these major agencies in it to reduce any type of overlooked error on your report file.