Buyers ask about American Express tradelines all the time, usually because they’ve seen an Amex card on a listing with 20 years of history and assume that’s a huge score boost. It can be. But there’s a specific quirk in how Amex reports authorized users that changes the math entirely — and most buyers don’t know about it until they’ve already paid. Related reading: amex authorized user — covers the mechanics in more detail. Also: credit piggybacking — the broader context for how authorized user tradelines work.
How American Express Reports Authorized Users (This Is the Important Part)
Since around February 2015, American Express has reported authorized users differently from almost every other major issuer. When you’re added as an AU to an Amex card, the account appears on your credit report — but the “account open date” it shows is the date you were added, not the date the card was originally opened.
This matters enormously. If someone has had their Amex card since 2004 — that’s 20 years of history — and adds you as an authorized user today, your report shows an account opened this month. Not 2004. This month. So instead of getting a 20-year-old account that boosts your average credit age, you get a brand-new account that might actually lower it.
This is why Amex tradelines sell for lower prices than their raw stats would suggest, and why a seller listing an Amex card is, in my experience, often overselling what the buyer will actually receive. The credit limit still counts — you pick up the available credit and utilization benefit — but the age benefit, which is one of the main reasons people buy tradelines, is essentially gone.
(I want to be clear about where this information comes from: this is industry knowledge from selling tradelines and watching what actually posts on buyers’ reports. It’s not from Amex directly. But it’s been consistent enough across enough reports that it’s not a rumor — it’s how the system works.)
What Amex Tradelines Still Do for Your Score
The Amex quirk doesn’t make their tradelines worthless — it just changes what you’re buying.
What you still get as an Amex authorized user: the credit limit (which reduces your overall utilization ratio) and the payment history (clean on-time payments count regardless of the open date). If the Amex card has a $25,000 limit and you’re currently showing high utilization across your other cards, adding that limit to your available credit can still move your score.
What you don’t really get: the age. The account will post as opened recently, which means it might actually drag down your average account age slightly if it’s lower than your current average.
So an Amex tradeline is most valuable when the goal is purely utilization — you need more available credit to lower your utilization ratio, and age doesn’t matter for your specific situation. It’s least valuable for thin-file buyers who specifically need older accounts to build up their average account age.
What Makes a Good Tradeline (If Not Amex)
The issuers that work best for authorized user tradelines — from a buyer’s perspective — are the ones that report the original account open date, not the AU add date. That’s most major issuers: Capital One, Chase, Barclays, US Bank, Fidelity — they all report the original open date, which is what gives the tradeline its age value.
Chase cards tend to sell faster in the tradeline market because buyers recognize the name. But from a credit impact standpoint, a Chase card and a Capital One card from the same year with the same limit do essentially the same thing. The issuer’s brand carries zero weight in the FICO algorithm. The limit, age, and payment history are everything.
One issuer specifically worth knowing about: Citi. Citi has a known history of not posting authorized user accounts to all three bureaus consistently. If you buy a Citi tradeline, there’s a higher-than-average chance it doesn’t show up where you need it. I wouldn’t buy one. Bank of America carries its own risks on the seller side — BoA has been known to close cards when they suspect tradeline activity, which is a problem for sellers (I lost a $40,000 BoA card to exactly this), but it doesn’t affect buyers who already have the account posted.
How to Evaluate an Amex Listing Before You Buy
If you’re looking at a tradeline listing and it’s an Amex card, here’s how I’d evaluate it:
What’s the limit? If it’s high — $20,000 or more — and your utilization is currently a problem, the Amex still helps on that dimension. If your utilization is already low and you mainly need age, look at a different card.
What’s the price? Amex tradelines should be priced below comparable non-Amex tradelines of the same age and limit, specifically because the age benefit doesn’t transfer. If someone is charging the same price for a 15-year-old Amex as a 15-year-old Capital One, the Capital One is the better buy for most purposes.
What’s your specific goal? If you’re trying to qualify for a mortgage and the lender specifically asked about utilization, the Amex might work. If you’re trying to build average account age for a thin file, it probably won’t.
The Bottom Line on Amex Tradelines
Amex tradelines have real value in specific situations — mainly when utilization is the primary issue. They’re not a ripoff, but they’re frequently sold without the buyer understanding the account-age limitation, which leads to disappointment. The credit limit still counts. The age benefit largely doesn’t transfer. Know what you’re getting.
If you have questions about which type of tradeline fits your specific situation, our tradelines FAQ covers the most common scenarios. And if you want to see what’s currently available — including both Amex and non-Amex options with full details on each — browse the current listings here.
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