Assume someone has a fairly decent credit/history/score, no lates,no deragatory accounts - but ONLY source of income Social Security, or SSI. This person applies for a credit card, and lists his/her SS income in the annual income section on the application. Assume the monthly benefit amount is $1200. This translates into $14,400 annually. But this person, only on Social Security is not required to file taxes. This then in reality is NET income, not gtoss. While in the employment related area this person could mark the "retired" box and in the income related box $14,400, a potential creditor, credit card outfit, would probably not approve/issue a high limit card, therefore in reality discriminating against retired folks whose only source of income is Social Security.
I'm not sure what point you're trying to cover here, but "gross income is gross income". Because taxes can fluctuate widely, credit issuers ask for the gross income. The "tax benefit" of SS income would not make much difference in this scenario. If this were the only income, the other factors of credit score, report history would determine the CL on a credit card. I don't believe there is any real discrimination here.
If you only have $1200 a month in Social Security, you probably shouldn't be looking at a high-limit card anyway. It can cause you problems as you are tempted to buy things you can't afford. If there are other sources of income that could help pay off the high-limit card (investments, etc) then they should be included in the income. If, for example, you get $3600 in dividends from investments each year, that's another $300 per month in income.
