A part or instalment, often of a large sum of money. Typically refers to different classes of securities e.g. 'A' Tranche and 'B' Tranche in a securitisation. Can also more generally mean an issue of a certain amount of securities e.g. a £100m "tranche".
An issuance mechanism by which a security -identified by its code-is issued in successive auctions. Securities with exactly the same features thus join other securities previously issued, all of them being fully fungible. The main goal is to reach a total size for the security big enough to ensure liquidity in the secondary market.
Related securities that are offered at the same time, but have different risks, rewards, and/or maturities.
Another issue of existing stock, usually a fixed income term.