Hybrid securities are a broad group of securities that combine the elements of the two broader groups of securities, debt and equity.
Hybrid securities pay a predictable (fixed or floating) rate of return or dividend until a certain date, at which point the holder has a number of options including converting the securities into the underlying share.
Therefore, unlike a share of stock (equity) the holder has a 'known' cash flow, and, unlike a fixed interest security (debt) there is an option to convert to the underlying equity. More common examples include convertible and converting preference shares.
A hybrid security is structured differently and while the price of some securities behave more like fixed interest securities, others behave more like the underlying shares into which they convert.
Traditional hybrids were usually structured in a way that leads the securities to react to the underlying share price. Although each has individual characteristics, typically: