Not even Darren Robbins can say exactly how much money he’s recovered for his investor clients in securities class actions over the years–it depends on how you calculate it, he explains. Suffice to say, it’s well in the billions. In the last month alone, his firm, Robbins Geller Rudman & Dowd, racked up more than $500 million in settlements.

Originally from San Bernardino, California, Robbins, 49, said he became a lawyer because it was a way to make a difference. He’s now one of the most successful advocates ever for injured shareholders, as well as co-founder of a firm that ranked first in both the number and dollar value of securities class action settlements last year –$1.5 billion, according to ISS.