Social Rank

Social rank refers to the social system used in Yuppie Psycho.

Function
The social ranking system is a hierarchy that appears to judge who can work as what within the society in the game.

Mr. Chapman talks about how 'the more important you are, the higher the floor you work on is.' (Ironically, he's only able to get to the second floor).

Assuming he's correct, and taking into account the fact Brian ascended to class A at the beginning of the game thanks to the offer letter, there's a possibility each floor is decided on rank.

Class A is considered highest.

Class G is considered extremely low, though it's not known if this is the lowest rank.

Class R is considered to be even lower then class G, Hugo explaining during his backstory at the end of the regular route of the game, claiming that people of Class R people don't get names, but instead are assigned numbers.