Medallion Signature Guarantee Definition

What is a medallion signature guarantee? A medallion signature guarantee is a financial designation affixed to a document that affirms the identity of the signer of the document.  The institution that issues the guarantee accepts liability for any potential fraud associated with the identity of the signer.

In order to conduct a medallion signature guarantee, a transfer agent must be licensed with one of three main medallion signature programs:
  • New York Stock Exchange Medallion Signature Program
  • Stock Exchanges Medallion Program
  • Securities Transfer Agents Medallion Program
A medallion signature guarantee uses a physical stamp that is affixed to the document, adjacent to the signature.  The transfer agents who issue a medallion signature guarantee formerly used an actual medallion to mark a document.  The guarantees are typically made with an ink stamp now, but the name still includes the word "medallion" as a reference to the past.