A security (Swedish: värdepapper) is a document or a registered right that gives its holder a right that can usually be converted into money. Common examples are shares, bonds, warrants and convertibles. Securities are part of the broader category of financial instruments.
Many securities were once represented by physical documents, such as share certificates. Today they are increasingly registered digitally. For shares in a limited company, it is the share ledger that shows who owns which shares, whether or not share certificates have been issued.

Financial instruments is a collective term for, among other things, shares, bonds, fund units and derivatives.
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A share is a unit of ownership in a limited company that gives the right to vote and to receive dividends.
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A share certificate is written proof that a person owns certain shares in a limited company.
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An issuer is the company or organization that issues shares or other securities to investors.
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