When voting to close a question as off-topic in the main site, we have the option to check as reason,

> "This question belongs on another site in the Stack Exchange network"

Then a new window opens... **and the only option we get is that the question belongs to the meta of economics.se.** 

I don't know if this is a bug or deliberate, but if it is deliberate, it renders the option totally useless -the point is to be able to select among the SE sites.  

I understand that migration itself (decision and execution) is and should be the responsibility of moderators, but we should be able to indicate to them what site we think is the appropriate one, to avoid duplication of effort.

I checked the same feature in Cross Validated, and there, one gets the option, apart from migration to meta, to indicate math.se and stackoverflow.

Then I guess someone, either a moderator or an SE-associate could (and should) add to our choices in the main for off-topic/migration suggestions, the following four sites

https://money.stackexchange.com/  

http://quant.stackexchange.com/  

https://stats.stackexchange.com/  
  
https://math.stackexchange.com/