AEI Income & Growth Fund XXI is a Minnesota limited partnership formed in 1994 to acquire, lease, and sell commercial real estate in the U.S. The partnership raised $24M from limited partners to purchase ten commercial properties at a total cost of roughly $19.7M. The core business is owning single-tenant commercial buildings and leasing them to tenants under net leases, where tenants cover property taxes, insurance, and maintenance, allowing rental income to flow through with minimal property-level costs. The partnership owns its properties debt-free, so there is no interest expense or leverage risk. The partnership is now in wind-down mode, selling off remaining properties as part of a final liquidation. As of year-end 2025, the partnership held interests in four properties. Four tenants account for 97% of rental income, meaning results are almost entirely dependent on a small number of tenants. Returns to limited partners come from monthly rental distributions and proceeds from property sales during liquidation.