Key Takeaways
- On the pages I read, neither FICO nor VantageScore says how an authorized-user account's age compares with its credit limit. Each publishes a category chart for consumers as a whole, and the two charts do not match.
- On one thin file (two cards, 16 and 8 months old, $2,500 of limit, 32 percent utilization), a 12-year $2,000 card reported with its original open date would put the oldest account at 144 months and the plain average at 56. A 2-year $25,000 card would put them at 24 and 16. The plain average is my own arithmetic, and the FICO and VantageScore pages I read give no formula for it.
- If reported, the same two cards would put the overall ratio on the report at 20 percent and about 4.7 percent, at the balances they last reported. A report carries a card's balance along with its limit.
- By the arithmetic, the overall ratio is lower with an added card only while that card's own ratio is under the one already on the file. With $15,000 on the $25,000 card, this file would show about 57.5 percent in place of 32.
- myFICO says its category percentages are for the general population, and that recent FICO versions give authorized-user accounts less impact than primary accounts. It does not say how much less.
- Fannie Mae's Selling Guide topic B3-5.3-06 says authorized-user tradelines cannot be considered on manually underwritten loans, with listed exceptions. Topic B3-5.3-09 says Desktop Underwriter takes them into consideration.
The Question Has No Published Answer
Two relatives offered to add me as an authorized user in the same month. My aunt has a card she opened twelve years ago with a $2,000 limit. My cousin has one he opened two years ago with a $25,000 limit. Either could appear on my credit report as a new tradeline, which is an account as a report lists it. On a file as thin as mine, I wanted to know whether the age or the limit counts for more.
authorized user
A person the account owner permits to have access to and use a credit account without owning it.
On the pages I read, neither FICO nor VantageScore says how an authorized-user account's age compares with its credit limit. Each company publishes a chart of score categories for consumers as a whole, and the two charts disagree.
I can compute, to the dollar and the month, what each card would change on my credit report, then set those changes beside what myFICO, VantageScore and Fannie Mae have published. The arithmetic covers a single file, my own. Results vary from file to file, and nothing here predicts what either card would do to a score.
My File Before Anyone Adds Anything
I have two credit cards, both in my own name, and nothing else.
The oldest account is 16 months old, the newest is 8, and the plain average of the two, my own arithmetic, is 12. My revolving limits add up to $2,500 ($1,000 plus $1,500) and my reported balances to $800 ($380 plus $420), so my overall utilization is 800 divided by 2,500, or 32 percent. Card by card it is 38 percent on the first and 28 percent on the second.
utilization
The percentage of available revolving credit in use, worked out from the balances and credit limits on a credit report.
Two Cards, Three Columns
I asked both relatives for the month the card was opened, the credit limit and the latest statement balance. My aunt's card is 144 months old, has a $2,000 limit, and last reported $100. My cousin's is 24 months old, has a $25,000 limit, and last reported $500. Both said they have never paid late.
The table shows my file three ways: as it stands, and as a report would list it with my aunt's card or with my cousin's, if each is reported with those figures.
One Thin File, Three Ways
| Figure | Now | Old card | Big card |
|---|---|---|---|
| Oldest account | 16 mo | 144 mo | 24 mo |
| Newest account | 8 mo | 8 mo | 8 mo |
| Plain average | 12 mo | 56 mo | 16 mo |
| Total limit | $2,500 | $4,500 | $27,500 |
| Balances | $800 | $900 | $1,300 |
| Overall ratio | 32% | 20% | 4.7% |
| Highest card | 38% | 38% | 38% |
The added card's own ratio is 5 percent for my aunt's and 2 percent for my cousin's. Both are under my own 38 percent, which is why the last row reads 38 percent in every column.
The average row is my arithmetic, a plain mean of the ages: 168 months divided by 3 is 56, and 48 divided by 3 is 16. The myFICO and VantageScore pages I read give no formula for average age, so the row describes the report and says nothing about what a model computes. It also assumes that the issuer reports the account and that each bureau lists the card's original open date, which I would check on the report once the account posted.
What the Old Card Changes: The Age Rows
In the oldest-account and average rows, my aunt's column sits much further from today's figures than my cousin's does. The oldest account on the report would be 144 months old in place of 16, a difference of 128 months; with my cousin's card the difference would be 8. My plain average would be 44 months higher with her card and 4 with his.
I infer this much: if a model reads the open dates the way the report prints them, the old card would change the oldest-account and average figures more than the young one would. Whether a given score version reads an authorized-user account that way, and how much the change would count, is not published on any page I found.
What the Big Card Changes: A Limit Is a Denominator
The post says could, and it does not say when an authorized-user card is included and when it is left out, so I do not assume the ratio on my report is the ratio a score uses.
On the report itself, with his $25,000 limit and $500 balance listed, my overall ratio would be about 4.7 percent in place of 32, which is 27.3 percentage points lower. With her $2,000 limit and $100 balance listed it would be 20 percent, 12 percentage points lower.
I do not control one of the inputs: the limit arrives on my report together with whatever balance the issuer reports that month. Suppose his card reports $15,000. My file would then show $15,800 against $27,500, about 57.5 percent, and its highest single-card ratio would be his 60 percent in place of my own 38. The card's age and limit are the same in both examples; the reported balance alone would put the overall ratio under 32 percent in one and over it in the other.
The break-even line on this file
An added card reported at 32 percent of its own limit would leave this file at 32 percent overall: $8,000 on the $25,000 card, $640 on the $2,000 card. A larger reported balance would put the overall ratio above 32 percent, a smaller one below it.
Why the Published Charts Cannot Settle It
The old card's column differs most in the age rows and the big card's in the utilization rows, so a category chart looks like a way to weigh one against the other. myFICO's chart gives amounts owed 30 percent and length of credit history 15 percent, which would make the limit look twice as important. I do not use the chart that way because of what the same page says about it.
The page says the importance of these categories "may vary from one person to another", and that scores for people who have not been using credit long "will be calculated differently than those with a longer credit history", which describes me. The chart's levels of importance, it adds, "are for the general population and may be different for different credit profiles." My question is about a single profile, and a thin one.
Two Published Charts
| Source | Usage | Age |
|---|---|---|
| myFICO chart | Amounts owed 30% | History length 15% |
| VantageScore 4.0 | Utilization 20% | Depth (age, types) 20% |
| VantageScore site | Highly influential | Highly influential |
On authorized-user accounts in particular, myFICO's FAQ says: "In recent versions of the score, authorized user accounts have less impact to your FICO Score than primary accounts." In older versions, it says, they "are treated the same as the primary account holder's." The FAQ does not say how much less, or which versions count as recent. The VantageScore User Guide has one line under the heading Authorized User: the impact of renting authorized user trades to move a score "is minimized." It does not say how.
A Lender Can Set the Account Aside: A Mortgage Example
myFICO notes that a FICO Score "is calculated only from the information in your credit report", while lenders "may look at many things when making a credit decision". Fannie Mae publishes a written rule about authorized-user accounts. It covers mortgages and says nothing about card or auto lenders.
My own two cards fall outside every authorized-user caveat in this post. If their statements report $100 and $150 in place of $380 and $420, my balances are $250 against $2,500: 10 percent overall and 10 percent on each card.
What I Can Verify on My Own Reports
I wrote down what I can check myself. Every item is on a credit report or in a document quoted above.
What the Sources Say About an Authorized-User Entry
I have taken neither offer yet. I paid down my own two cards first, the accounts where I am the primary holder, and then asked my aunt and my cousin for their next statements, since one month's balance is a single reading.
I still cannot say whether twelve years counts for more than twenty-five thousand dollars, because no page I read says which.
myFICO's FAQ ends its answer on authorized users with a line about the other kind of account: "it's also important to have credit accounts where you are the primary account holder." I have two of those, 16 and 8 months old. Next month they will be 17 and 9, with either relative's card on my report or with neither.
Frequently Asked Questions
1. Which matters more on an authorized-user account, its age or its credit limit?
On the FICO and VantageScore pages I read, neither company says how an authorized-user account's age compares with its limit. The category charts each publishes are for consumers in general. VantageScore's consumer FAQ names, in one sentence, a card that has been in circulation longer, has a high credit limit and pays on time, and it does not rank the three.
2. Does a high-limit authorized-user card always make my utilization lower?
No. A report carries a card's balance along with its limit. By the arithmetic, the overall ratio is lower only while the added card's own ratio is under the one already on the file. On the file in this post, a $25,000 card reported with a $500 balance would put the overall ratio at about 4.7 percent in place of 32, and the same card reported with $15,000 would put it at about 57.5 percent.
3. Does an authorized-user account's age count in my average age of accounts?
myFICO lists the age of your oldest account, the age of your newest account and an average age of all your accounts under length of credit history. The pages I read do not say whether an authorized-user account's age enters that average, and they give no formula for it. The plain average in this post is my arithmetic on the open dates a report would list.
4. Can I use the published category percentages to compare age and limit?
Not for one file. myFICO's chart gives amounts owed 30 percent and length of credit history 15 percent, and says those levels are for the general population and may be different for different credit profiles. VantageScore's 4.0 figures are 20 percent for utilization and 20 percent for depth of credit, which its User Guide describes as an average of all consumers.
5. Do authorized-user accounts count the same as my own accounts?
myFICO's FAQ says that in recent versions of the FICO Score authorized-user accounts have less impact than primary accounts, and that older versions treat them the same as the primary account holder's. It does not say how much less or which versions count as recent. VantageScore's 4.0 User Guide says the impact of renting authorized user trades to move a score is minimized.
6. Does a mortgage lender count an authorized-user account?
It depends on how the loan is underwritten. Fannie Mae's Selling Guide topic B3-5.3-06 says that for manually underwritten loans, authorized-user tradelines cannot be considered in the underwriting decision, with exceptions: another borrower on the mortgage owns the account, the borrower documents being the actual and sole payer for at least 12 months before the application date, or the owner is a spouse who is not a borrower. Topic B3-5.3-09 says Desktop Underwriter takes authorized-user tradelines into consideration.
7. Can an authorized-user account by itself get me a FICO Score?
myFICO lists the minimum as at least one account opened for six months or more, at least one account reported within the past six months, and no indication of deceased on the report, and says a single account may satisfy the criteria. That page does not say whether an authorized-user account counts, so I treat it as unknown.
8. Is paying for an authorized-user tradeline legal?
This post gives no verdict. The FTC's complaint against a company that sold piggybacking, filed in March 2020, states that the agency has never determined that credit piggybacking is legal. Announcing the settlement, the director of its Bureau of Consumer Protection said good credit isn't for sale.