No mortgage instrument shall be registered except with the prior written consent of all the holders of mortgages then registered against the ship concerned.

The instrument is a form of senior debt that is paid back from the issuer's cash flows but is also secured against a ring-fenced pool of assets, such as mortgage loans, in the event of default.

The instrument in question, structured and marketed by Goldman, was a synthetic collateralised debt obligation (CDO), whose performance was tied to that of residential mortgage-backed securities.