Renewable fuel producers are parties that produce renewable fuel (i.e. convert a renewable feedstock into a renewable fuel). RINs must be generated by the producer and assigned to renewable fuel by the time title to the renewable fuel is transferred from the producer to another party such as a marketer. See regulation Sections 80.1126(d)(1) and (e)(2). In turn, the marketer must transfer assigned RINs to the party to whom the marketing company sells the ethanol.
Marketing companies who "represent" renewable fuel producers are not producers unless the marketing company produces renewable fuel, and such a company would only generate RINs for that part of the renewable fuel that they actually produced. Ethanol marketing companies that do not produce or import renewable fuels are not renewable fuel producers or importers and cannot generate RINs.
Question and Answer was originally posted at: Questions and Answers on the Renewable Fuel Standard Program (PDF) (55 pp, 221 K, EPA420-F-07-041a, August 2007, About PDF)