A nongovernmental output property bond is a bond that is treated as a private activity bond even though it is not issued for a private activity. This can occur when the bond finances a project that is not a traditional private activity but still has a significant public purpose or benefit. A qualified mortgage bond, on the other hand, is a bond issued for financing the acquisition, construction, or refinancing of one- to four-family residential rental property. These bonds are designed to encourage the development of affordable rental housing and offer tax incentives to investors to help make these projects financially viable.