Let's divide "adverse action" between two dovetailing Regs, Reg B, not applicable here, and FCRA, definitely applicable here.
The FCRA requires a notice when a product or service is denied, and you based that decision in whole or in part on a consumer credit report. FCRA 615.
This is why ChexSystems and the likes provide AAN pads to those using the service. Qualifile uses ChexSystems as I recall.
My opinions are not necessarily my employers.
Rules and Regs minus Relationships equals Resentment and Rebellion. John Maxwell