Eidos parent SCi revealed that it was set to sell the offshoot in its trading update yesterday.
A source close to the deal told MCV: "SCi wants rid as part of their restructuring, and this makes perfect sense for Koch. It's a snug fit for their strategy of growing their global presence."
The official announcement is due immently.
UPDATE: SCi Entertainment has now confirmed the deal.
SCi CEO Phil Rogers said, "Selling the Proein business is in line with our declared strategy to have a lean and efficient approach to distribution to support our product focused, studio-led business model.
"Proein has a history of building business with Eidos and other publishers and we look forward to working with them as our distribution partner in the future."
According to SCi, Proein's gross assets as of the end of June 2008 were 8.6 million Euros.