Over the past decade covered bonds, or securities issued by financial institutions that are secured by dedicated collateral, have become one of the largest asset classes in the European bond market and an important source of finance for mortgage lending. The collateral, or “cover pool”, is usually put together so as to obtain the highest possible triple-A credit rating. As a consequence, covered bonds offer an alternative to developed country government securities for bond investors interested in only the most highly rated securities. Drawing on the BIS international debt securities statistics and other data sources, this feature analyses the recent evolution of the covered bond market. Exploring the main issues.