Under what condition is a loan considered "open-end" or "revolving credit"?

A loan is considered "open-end" or "revolving credit" when it allows consumers to borrow, repay, and borrow again. This characteristic is fundamental to the nature of revolving credit, such as credit cards or lines of credit, where borrowers have a credit limit and can draw from it as needed, repay the borrowed amount, and then borrow again without the need to apply for a new loan each time.

Open-end loans provide flexibility to borrowers since they can manage their borrowing based on their needs rather than adhering to a fixed schedule of payments associated with installment loans. This feature encourages ongoing use of the credit line and supports varying repayment amounts depending on how much is borrowed at any given time.

The other options describe characteristics of different types of loans. Fixed monthly payments generally pertain to closed-end loans where the payment structure is predetermined. A lump sum payment usually relates to a single payment loan format, not an open-end loan. Lastly, the requirement of being secured by real estate refers to a specific type of loan, such as a mortgage, which does not necessarily involve the revolving nature of open-end credit.