"In playing ball, and in life, a person occasionally gets the opportunity to do something great. When that time comes, only two things matter: being prepared to seize the moment and having the courage to take your best swing."Hank Aaron ** The executive summary for Alphacution case study, "The Rise of Hudson River Trading," is also available for free download (with registration) in our Reports Library ** Introduction As if on cue, and apropos of the times, a tweet by Joe Gawronski, President of Rosenblatt Securities states that December 24, 2020 marked the first time ever that off-exchange trading represented the majority of US equity volume (50.38%): Rewinding from there to a Reuters article dated January 16, 2018 entitled “Hudson River Trading to buy rival HFT firm Sun Trading,” HRT’s co-founder and director, Jason Carroll, said in a statement, “This acquisition combines HRT’s expertise in on-exchange trading with Sun’s expertise in off-exchange trading creating a stronger, more diverse firm.” What happens between these two points in time is no accident. [...]