Knowing what we do about Pound's personal views on modern economics, it's really impossible to say that the speaker of Canto XLV is anyone other than Pound himself. In earlier Cantos, like I and II, Pound is happy to adopt the voices of ancient poets like Homer and Ovid. But by the time he reaches Canto XLV, Pound is ready to take up the role of speaker himself.
And not only is it Pound speaking, but it's Pound speaking as though he were some sort of Christian God. You can tell by the way he uses language that Pound thinks pretty highly of his moral position. Lines calling usura a "sin against nature" (14) are one thing; but saying the same thing in Latin and with all caps ("CONTRA NATURAM") makes Pound sound especially angry and godlike.