We have determined that home values in your area, including your home value, have significantly declined. As a result of this decline, your home's value no longer supports the current credit limit for your home equity line of credit. Therefore, we are suspending your account immediately.... Please understand that this suspension of your account was not based on your payment record. Rather, the change is being made simply because your home value has declined, and Citibank wants to help protect you from borrowing beyond the value of your home.