There are risks associated with sale-leasebacks.  The following is an overview of some of the key risks, but does not represent all risks in their entirety:

Tenant Credit Risk.  First and foremost, the credit risk of the tenant should be considered. Investors are relying on one tenant's business success. It is imperative in the due diligence process to verify that the estimated return on the property appropriately compensates the investor for the risk level of the tenant.  If your tenant defaults or files bankruptcy, there may be a period of nonpayment of rent followed by a renegotiation of the lease.

Tenant Improvements.  By customizing the real estate property for one particular type of tenant, there may be remodeling or redevelopment costs at the time of the lease renewal or when you replace the original tenant.

Overvalued Leases.  It is not atypical to see leases that are above market rents on Net Leased properties.  This occurs because the original tenant's business model justifies the cost of the lease and improvements, but that value may not tranlate to other tenants.  In the event the tenant terminates or completes the occupany prior to the original planned exit, the owner could bare financial risk to the difference in market and original tenant rates.  The difference in rent values could substantially affect the market value of the property.  

 Systemic Market Risk.  As with any real estate investment, there are systemic risks associated with holding real estate.  Net Lease investments are not immune to these risks.