REITs typically focus on a specific niche within real estate, so investors can quickly build a portfolio with exposure to many property types and generate the passive income they need without having to have a fortune already. It creates steady growth by signing leases averaging almost 11 years in length, and its contracts include escalators that often reflect inflation rates. E-commerce is slowly eating up a share of retail sales in the United States, but if you believe in the long-term health of premium shopping centers, Simon Property Group is arguably the most dominant REIT in its space.