The ones closest to the money printer. Hot money gets the advantage of lower prices before that newly-printed money impacts those prices.
So, who? The private owners of the Fed.
Discussion
You might have heard of the Cantillion effect? This is that.
Makes sense, this apply to any money including the dollar. So who exactly are the private owners of the feds?
I don't know that that is officially released, but a safe bet would be the families/banks that set it up (in secret) to begin with... see James Corbett's 'Century of Slavery' video
So this cantillion effect is less about being close to the printer and more about being close to the blood line.
I wouldn't go quite that far. The 'big families' certainly are behind this at the very top--but the brokers and clearing houses and 'bond agents' (or whatever they're called) take a little cut out of every transaction.