EA has chosen not to allows developer Turn 10 Studios to feature the Porsche range of cars in its upcoming title, Forza Motorsport 4.
EA owns the exclusive rights to feature Porsche vehicles in its games, but in the past has reached agreements with the Forza franchise through sub-licensing deals.
Writing on the official Forza Motorsport blog community manager Brian Ekberg explained that was not the case this time.
"EA couldn't see their way towards collaborating again," he said, addressing fans of the series.
"We've asked our contacts at EA to reconsider their position frequently and regularly over the last 18 months. We also reached out to various influential people in gaming to lobby on our behalf, and on your behalf, but that was to no avail."
He also wrote that Turn 10 had approached "key people in Porsche circles," who also campaigned on its behalf.
The Forza franchise currently has the exclusive license for Ferrari vehicles on Xbox and PC.
"We've always found that we just weren't willing to block other racing games from having Ferraris outright, as we believed that this would do nothing but hurt the racing ecosystem."
Turn 10 is a Microsoft studio based in Washington, and develops the Forza Motorsport series for Xbox, starting with the original title in 2005.