This is a financial instrument with a half-way position (hybrid) in a company's capital structure. Mezzanine stands between equity capital and those bank loans which are secured in some way by the company's assets.
In connection with larger business acquisitions, financing is structured in an optimal way with a variety of different financing forms (instruments) which supplement each other, and in which mezzanine financing plays a major role. The investors (the new owners) want to balance equity capital and loans in order to achieve the best return in relation to risk and financing costs.
Mezzanine financing bridges the gap between the loans which the bank offers and the equity capital which the investors have available. In order to make mezzanine loans attractive, both a higher interest rate than the interest rates which are offered on bank loans, and better priority rights than the shareholders have, are offered. The loan may even, in some situations, be convertible to shares.
The word mezzanine derives from the Italian word "mezzano" (middle) and is used for, among other things, an extra floor in a building.