recently regemmed and i have 51.4% arp (including the 10% through deep blood talents).
with the grim toll proc its ~101%
i read somewhere that it capped out at 100%, then i remember them saying you could go over 100% into the negatives or something to that effect, just not sure which order they said these two things.
anyone know which it currently is or could provide a link to an armory with someone stacking high amounts or arp would be helpful.