Why do FICO Scores fluctuate/ change?

There are many reasons why your 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 particular consumer reporting agency at that time. So, as the information in your credit file at that bureau changes, your 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 changes in FICO®Scores. Keep in mind that certain events such as late payments or bankruptcy can lower your FICO® Scores quickly.