You get 1 pledge ring for every 100 pledges. Then 5 pledge rings combine to a frat ring or something. So your individual bonuses increase as well.
I believe camillie is right based on the OP. It says if you get at least 100 pledges you get a ring. I assume that's each round and if you manage it in 5 rounds (5 rings in total) then you get the special one?
My understanding is that every 100 pledges leads to a ring. There wasn't any limit stated. So if you get 1000 pledges in one day, you get 2 frat rings.
I'm really not sure about this. Pimd_c have been frequently posting. Hopefully will shed some light soon
Or just after the first round we will know really, I should have 200+ so will know if I got more than 1 ring