The overall category of utilization of credit has two components: % util of revolving credit, and % balance remaining on installment credit.
Scoring is highly weighted towards % util of revolving as opposed to % balance of installments, as they have very different impacts on risk of repayment of debt.
Installment loans show debt. You enter into a contract, receive one slug of $, and repay in set amounts.
You dont have the discretion to increase that credit.
Thus, you dont have a % util. You have a % remaining of balance.
Installment loans are often secured by property the consumer wants to protect, so are usually the last to become delinquent should times get tough, and thus they are generally not given much weight in the FICO risk of repayment analysis. Not sure how much unsecured loans may have a higher risk consideration in scoring.
If the question is whether installment counts in your % util scoring, the answer is no.
If the qeustion is how much a student loan affects installment scoring, I have never seen a FICO pronouncement on that issue.
Revolving accounts give you a discretionary amount to use, and thus you can increase your debt at any time up to that limit.
That discretion represents higher risk of debt, and higher debt can represent higher risk of timeliness of its repayment.
Thus, % util of revolving is given much more weight in the FICO risk of repayment analysis.
When you request a CLI on a revolving, it is obviously fair game to look at your overall indebtedness as a factor in determining the issue of whether more discretionary credit should be granted. Installment debt can be a factor in that decision, but not in FICO analysis of your % util of revolving debt.
