EQ's FICO 8, unlike EX and TU, uses charge card balances in utilization. Up to a point. What it uses is the "high balance" component of charge cards.
Here's an example of the last 5 months showing only Amex alerts and associated EQ FICO 8 score changes (all numbers rounded to the first digit):
EQ Alert: Balance change 1k -> 2k FICO 8 774->770 (High Balance 20k)
EQ Alert: Balance change 2k -> 40k FICO 8 782->763 (High Balance (40k)
EQ Alert: Balance change 40k -> 4k FICO 8 760->795 (High Balance (40k)
EQ Alert: Balance change 4k -> 60k FICO 8 801->802 (High Balance (60k)
EQ Alert: Balance change 60k -> 3k FICO 8 794->794 (High Balance (60k)
My non-Amex CLs total just over 50k Overall util excluding Amex varied from 2% to 8%. Including Amex and using the high balance as a proxy, util varied up to 40% with the 40k H/B and 60% with the 60k H/B.
Once my high balance went to 60k the Amex stopped affecting FICO scores.
@RaiseMyScoreASAP wrote:So question--Let's say you only have two cards--one AMEX Platinum and one CSP with a credit limit of $50K. The highest reported balance you have had on the AMEX was $50K. So let's say this month, you had $5K reported on your CSP and a $0 balance on AMEX. Would your total utilization on EQ be 5% and your total utilization on TU and EX be 10%? Say the next month you have $10K reporting CSP and $50K reporting on AMEX would that mean your TU and EX utilization would be 20% but your EQ utiltization would be 55%?
So to me it would make sense to have one month have AMEX reporting the highest possible balance you ever could have to establish your high credit which will operate as your proxy CL, and then keep that card in the future to say no more than 7% reporting to get the maxiumum FICO points.
Thanks for answering. I am still learning.
The only (modern: FICO4 or FICO 8) score that Amex charge cards has ever affected is EQ's FICO 8, FICO 8 from TU and EX have always ignored my charge card balances. Also FICO 4 from all three CRAs ignored Amex balances. The older TU98 FICO did use Amex balances but that is almost never used anymore.
I have read that regular CCs with CLs somewhere over 45k are also ignored by FICO scoring. Don't have any that are even close to that so I can't speak to that personally.
Amex's reported high balance is not perpetual. It's the highest balance within the prior 18 months. Unfortunately for me, I now have to wait about 16 months for it to reset since at 60k it is no longer used for utilization in EQ's FICO 8. It also doesn't matter for the other CRAs since they don't use Amex charge card balances at all.