Can the bank raise my interest rate because of a change in my debt-to-income ratio?
Depending on the loan product, banks may change the interest rate on already-existing types of loans if they properly disclose the changes to you.
When setting the interest rate for a loan, banks take many factors into account. A common factor is the debt-to-income ratio (often abbreviated DTI), which is the percentage of a consumer's monthly gross income that goes toward paying debts.
Generally, the higher the ratio, the higher the perceived risk. Loans with higher risk are generally priced at a higher interest rate.