I am a co-signer on my son 's private student loan. He is entering his senior year of college and just filled out the paperwork for his last loan through Sallie Mae. The prior two years the fixed interest rate XXXX with me as a co-signer ) was 6.25 %. This year, the interest rate has increased to 9.25 %. When I talked to a manager, she said that the prior XXXX loans on my credit history made the interest rate go up. I have a good income, little debt and feel like Sallie Mae is just taking advantage of the fact that they have a near captive audience and can therefore raise the interest rate by 3 %, even with a co-signer. My son is attending the University of California XXXX. He has another undergraduate degree, so does n't qualify for federal loans.