Statute of Frauds
The Statute of Frauds requires certain agreements, including real estate sale contracts and long-term leases, to be in writing and signed before a court will enforce them. An oral deal to sell or lease real property for the long term generally will not hold up.
This is why documented transactions are the norm in commercial real estate. Any material agreement to convey or lease real property should be a signed, written contract, both to head off disputes and to keep it enforceable.