My ISP is about to close down. I want to keep the IP addresses they issued to me. Am I allowed to do that?

If the IP addresses assigned to your organisation have a status of "ASSIGNED PA" in the RIPE Database, they are Provider Aggregatable. That means you will not be able to take them with you when you change ISPs. Instead, you will have to renumber your network.

If the IP addresses assigned to your organisation have a status of "ASSIGNED PI" in the RIPE Database and the address space was assigned by the RIPE NCC, the IP addresses are Provider Independent. That means you can take them with you when you change ISPs.

If your LIR assigned address space to your organisation with "ASSIGNED PI" status, you might be able to take the IP addresses with you when changing ISPs. Please check with your LIR before you change ISPs.

The status of the addresses is visible in the inetnum object in the RIPE Database. You can query the RIPE Database online.

You can also read more about PA and PI address space in the RIPE Document, "IPv4 Address Allocation and Assignment Policies for the RIPE NCC Service Region" (section “Provider Independent versus Provider Aggregatable Address Space”)