There are many reasons why a score may change. FICO Scores are calculated each time they are requested, taking into consideration the information that is in your credit file from a consumer reporting agency at that time. So, as the information in your credit file at that consumer reporting agency changes, FICO Scores can also change. Review your key score factors, which explain what factors from your credit report most affected a score. Comparing key score factors from the two different time periods can help identify causes for a change in a FICO Score. Keep in mind that certain events such as late payments or bankruptcy can lower FICO Scores quickly.