Where do these Epson inks come from?

Bought a set of nine cartridges for the Epson R2880 from an affiliated seller on Amazon. The labels and all appearances were Epson; I could not any sign of counterfeit. The set was hand wrapped for shipment in a taped sheet of plastic.

After installation of several colors, prints seem fine. The price was considerably cheaper than charged by Epson and authorized retailers.

Do you know how these cartridges get into this sales channel? Overstock is one thing; gang-organized shoplifting or other theft is another that I would not want to support.