AEI Income & Growth Fund XXI Ltd Partnership is a U.S. real estate partnership that acquires and operates income-producing properties and generates returns primarily from rental income and property cash flows. Upon acquiring properties, it allocates purchase price between land/buildings and lease-related intangibles such as above- and below-market in-place leases, reflecting a business model focused on stabilized, leased assets. The partnership’s reported results are therefore closely tied to tenant lease terms, market rent movements, and property-level operating performance. It also evaluates properties for impairment when conditions indicate carrying values may not be recoverable, linking performance to local real estate market fundamentals.