Our company is offering courses in Business English.
To enable employees to assess their level of English a bit more objectively, they sent around a link to an online test which starts at a low level and lets you go to successively higher levels as long as you get enough points on the previous one.
I decided to take the test, too, partly for a lark but also partly because I'm not too confident on my Business English specifically; after all, it's not the sort of thing you learn at home or school.
The test told me that my score corresponded to level C2-3 (i.e. at the top [3 of 3 sub-levels] of level C2), "interpreter level". Well, well, well.
(FWIW, my self-assessment before I started the test was C2 for passive knowledge [listening, reading] and C1 for active knowledge [speaking, writing], mostly because I'm unsure whether I can capture the full breadth of stylistic variation they called for in their brief description of each level.)