Twin Bond Concept

All green Federal securities are always based on an existing conventional Federal security and have matching features. This creates twin bonds with identical coupons and identical maturity dates.
However, they have different issuance volumes: the conventional Federal security is in each case significantly larger than its green twin and is given its own securities identification number (ISIN).

The Twin Bonds of the Federal Government

The twin bond concept gives investors a deep insight into the structures of the market. This applies firstly to the price difference between conventional and green Federal securities, and secondly to the demand preferences of market participants for different maturity classes of green bonds.
Thanks to the additional transparency on allocated green spending in the Federal budget, green Federal securities basically have a higher value than conventional Federal securities - consequently, a greenium should emerge in the market.

Greenium - The Yield Difference of the Twin Bonds