An Estoppel Certificate (or Estoppel Letter) is a document often used in due diligence in Real estate and mortgage activities. It is a document often completed, but at least signed, by a tenant used in his or her landlord's proposed transaction with a third party. A mortgage lender intending to collateralize a tenant-occupied property or a purchaser intending to purchase such a property will often want to verify certain representations made by the landlord.
An estoppel certificate provides confirmation by the tenant of the terms of the rental agreement, such as the amount of rent, the amount of security deposit and the expiration of the agreement. Further, the estoppel certificate may give the opportunity to the tenant to explain if she may have any claims against the landlord, which may affect a buyer's or lender's decision to complete the proposed transaction.
Some lease agreements require the tenant to complete such a certificate or to waive his responses by allowing the landlord to complete the estoppel certificate under certain circumstances.