Credit scores are created through a software program--there is no mystery. A trade line or line of credit does not weigh in or count as valid until it is one year old. The opening of a new trade line is only negative when you do not treat it properly. When you open a new credit card, you do not want to charge more than 20% of the available balance. Also, you want to make your first payment on that balance as soon as possible so that it will report into consideration given by the score/ credit model. The credit model will look at your overall cumulative balances versus your cumulative amount of credit available.
Then, it goes to levels--how long is the trade line open? A trade line that is open longer can have a higher balance, and not upset the model. By opening a credit card, and having a high available balance, it will contribute to your overall “picture” in a more positive way. It will look at each credit card, how long they have been open, and how much is owed against it, and lastly, how many delinquencies you have. Any delinquency less than 2 years old will have a minimal effect. A current late payment of 30 days can cost you up to 40 points on your credit score. Some companies, after you bring the payment current, will allow you a one time courtesy of removing the late payment after you bring it current (make an on-time payment).