Because your "Spending Power" can change from moment to moment. If you start using the card for a bunch of small swipes, you may still have capacity above that for a large purchase, and the "large purchase" may keep extending out.
Similarly, if you've made a number of large purchases and your payment due date is approaching, the current spending power may get reigned in.
If they state a "Spending Power" number in a more permanent way, then that opens them up to certain expectations by the customer, which they don't want to fulfill. So it's a transaction by transaction analysis.
The above statements are not from some specific knowledge about how AMEX works, but the concept of NPSL is just different from point-in-time Spending Power. The concept of a Charge card, pay your bill in full, is also different from a revolving credit card.
AMEX plat- YPSL-$1000. Chase Sapphire Preferred- $1000. Citi Double Cash- $500. Chase Freedom-$500. AMEX BCP-$250 Amazon Visa Card-$100. Best buy-$9.95.
What are these numbers in your siggy? I only get the names of the cards. YPSL? CSP at $1,000? Please explain 
@Anonymous wrote:YPSL- Yes Pre Set Limit. (funny)
No Pre Set Limit = NPSL .....
Limit can change with each transaction
Lol
the sig is the cards I have. As for the limits, there might be a crazy story behind them..or not.
NPSL is based off average monthly spend. If you ring up 3k in small charges and pay that off. Eventually you can make one swipe with 3k. The internal limit is also based off your income because all charge cards must be paid in full. As for spending power, it's kind of the same to me
I had a question. PRG, if i leave a balance on it pass the closing date, and pay on the due date. Will my utilization be affected?
P.S. My info is straight from Amex account specialist