It is an official stamp that a corporation uses when executing legal contracts to show that the contract has been accepted and corrected, and that the execution was the act and deed of the company.

It was commonly used by corporations in common law jurisdictions before executing documents such as securities warrants, transferable bonds, legal arrangements, and so on, though most countries have abandoned it in modern times.  

How Does It Appear?  

It is essentially a pair of metal plates with lower and upper dies that, when pressed together on a piece of paper with a "red sticker," creates and embosses a print of the business name around the ring and the words "Common Seal" in the middle. Companies used red molten wax in the past, but it has since been replaced by a "red sticker."  

Singapore's Common Seal and its Legal Meaning  

According to the Companies (Amendment) Act, it is no longer mandatory for companies to affix a common seal while performing legal documents as of March 31, 2017.

Prior to the changes taking effect, corporations were expected to use a common seal to administer legal documents as a deed in compliance with the terms of their respective articles of association or constitution.