What must occur for bondholders to have a claim on a revenue source?

For bondholders to have a claim on a revenue source, it is essential that the revenue stream must remain intact. This means that the specific income generated from the operation or project funded by the bond issue continues to be sufficient to pay interest and principal to the bondholders. When bonds are issued backed by specific revenue sources, such as tolls from a toll road or fees from a public service, the stability and continuity of that revenue are paramount. If the revenue stream is disrupted or diminished, bondholders may face the risk of not receiving their expected payments.

The other options suggest conditions that, while they may be relevant to the broader context of bond investments, do not directly pertain to the fundamental requirement for bondholders' claims on revenue. For instance, investment grade ratings pertain to the perceived credit risk of the issuer but do not directly impact the claim on a revenue source. Similarly, the agreement of all bondholders on an investment or backing by assets may provide further security but does not address the critical need for the revenue stream to be intact to honor debt obligations.