When reviewing your credit report, Boom's tradeline may appear to be a loan or an open/closed account. The tradeline appears this way because the credit bureaus treat rental payments as a monthly requirements. Every monthly payment made fulfills the rental obligation for that given month.
Additionally, the tradeline may appear with a $0 balance. This is because of the monthly obligation that fulfills the payment requirement for rent reporting. As soon as that month's payment data is submitted to the credit bureaus, the balance will reflect $0 owed.