A recent highly disputed subject of regulating energy markets in Europe is the unbundling of vertically integrated down- and upstream firms. While legal unbundling is already implemented in most countries and indisputable in its necessity for approaching regulatory aims, continuative models as ownership unbundling or the alternative of an independent system operator are still ambiguous. Hence, this article contributes to the economic analyses of identifying the differences of separate types of unbundling. Via simulation, we find that legal unbundling brings about the lowest prices in a market under Cournot competition. Moreover, under Bertrand competition, no differences between legal unbundling and ownership unbundling can be identified. (author's abstract) / Series: Working Papers / Research Institute for Regulatory Economics