Mine just dropped 15 points the other day, and the only change I’m seeing is an old bank credit line at the bank that I closed years ago finally aged out of my record. Credit Karma rates my number of accounts “Poor” now because I only have one credit card and one student loan, though they’re both in good standing and my credit card utilization is always under 10% of its limit. Kind of a bummer.
Luckily the scores Credit Karma provides (Vantage) are almost completely meaningless. I've seen pretty huge differences between Vantage and FICO scoring, sometimes as much as 70 pts (as a frequent churner/bonus chaser, I monitor all my scores). Vantage Scoring is very rarely used in the real world. Credit Karma a useful platform for looking at your credit report, however. Here is a list of the credit cards that provide free FICO scoring and their associated models if you want to monitor your FICO at no cost. To make things even more confusing, not only are there 3 reporting agencies, there are also numerous FICO models. FICO 8 seems to be the most commonly used flavor currently, but version 9 was released some time ago. The confusing thing is that there is a normal FICO 8, a "Bankcard 8", and then an "Auto Score 8". So each version even has its own branches. I've seen my individual FICO 8 "branch" scores vary by as much as 50 points. Knowing my FICO bankcard 8 score even on all 3 reporting agencies isn't too helpful if I'm looking at getting a mortgage. Mortgage lenders for whatever reason tend to use an older version -- FICO Score 5. Yes, I have geeked out a bit on credit scoring.
Amex - Experian FICO 8 (amex started also providing Vantage, so make sure you're looking in right place)
Discover - Transunion FICO 8
Barclays - Transunion FICO (not sure model)
Citibank - Equifax FICO Bankcard 8
BoA Transunion FICO 8
So with an Amex/Discover/Citibank combo you could montior all 3.