Not really a UR specific question, but I'm at a loss. And so was a branch manager I spoke with a few years ago. Probably 10-15 years ago (its been a while) I wasn't in the best financial shape. I was late with an Amex payment (new bank account, and at the time Amex didn't tell you when your due date was when you set up autopay) and I picked an autopayment date that was after the due date (again, why no warning?) Payment was late by like three days, Amex reported it. A month later maybe, I got a call from Chase to do a financial review. The basically zeroed out my cards, and said if there wasn't a balance they'd have closed them all.

Flash forward to 2021. Everything is paid off, no debt aside from a car loan that had a few payments left. i use one of the cards specifically for business purchases, and it had about a $15k limit, and $20k would be way more helpful during busy months. I can handle the $15k, just means an extra payment needs to be made mid cycle. Called chase, hoping to get a CLI. No go. Barclay's increased without asking the limit on my View card from $1500 to $6500, Amex my Blue Everyday from $7500 to $12,500. Chase upgraded me from a regular Sapphire to the Sapphire Preferred. Two years go by, I ask for a CLI again. No go. Still no debt, the card gets used a lot, and paid in full every month. I go to a Chase branch, the manager calls someone, and I'm blocked from getting more credit from Chase for an unspecified reason. Which is annoying.

End of last year, tried again for a CLI with chase on our United card. Still denied. Since December I was able to get a BofA Alaska Card with $15k, a US Bank Smartly card at $23k, and a Fidelity Visa with $45k. This is in addition to my Amex getting random CLIs, as well as the Barclay's card. Very little has changed, if anything I have more debt with a mortgage and a car loan. But Chase won't budge.

Anyone have any ideas what happened?

That sounds incredibly frustrating. To have an impeccable credit profile now, with massive limits from conservative lenders like US Bank and Fidelity, only to be stonewalled by Chase over something that happened a decade ago is infuriating.
What you are experiencing is actually a known, albeit opaque, phenomenon in the credit card world. While I don't have access to Chase's proprietary underwriting algorithms, based on how their risk management departments operate, here is exactly what likely happened�and why you are still stuck in their penalty box.
### The Initial Trigger: Balance Chasing
When you had that late Amex payment 10-15 years ago, Amex reported it to the credit bureaus. Banks continuously run "soft pulls" on your credit to monitor your risk level. Chase's risk algorithm saw the sudden negative mark from Amex during a time when your overall financial profile wasn't at its strongest.
This triggered Chase's internal Financial Review. By slashing your limits down to your existing balances (and threatening to close them entirely), Chase was engaging in a practice called **"balance chasing."** It�s a defensive maneuver lenders use to mitigate their exposure when their algorithms decide a customer is at a higher risk of default.
### The Long Memory: Chase�s Internal Blacklist
You are likely dealing with an internal "do not extend credit" flag. Here is why it's still haunting you:
* **Internal Records vs. Credit Reports:** A late payment falls off your official credit report after seven years. As far as FICO is concerned, that Amex blip no longer exists. However, banks keep their own internal records and proprietary risk scores forever.
* **The Elephant�s Memory:** Chase is notorious in the credit industry for having an exceptionally long, unforgiving memory. If an account went to collections, was charged off, or triggered a severe adverse action (like a harsh Financial Review) in the past, Chase flags that profile internally.
* **The Unspecified Block:** When the branch manager called underwriting, they likely just saw a hard-coded restriction on your profile. Frontline customer service and branch managers do not have the clearance to override deep-level underwriting restrictions or see the specific algorithmic triggers behind them. They just see a red light.
### The "Siloed Account" Problem
It is also highly possible that the specific accounts you are asking for CLIs on are permanently "tainted" in Chase's system. Sometimes, a bank will permanently lock the credit limit on an account that survived a Financial Review, capping its growth forever, regardless of how much your external credit score improves. Upgrading the card (like going from the standard Sapphire to the Preferred) doesn't necessarily lift the internal limit cap on that specific trade line.
Have you ever tried calling the Chase Reconsideration Line specifically to speak with an underwriter, or have you considered applying for a completely new Chase card rather than asking for a CLI on the existing ones?

CLI = credit limit increase