PT Journal AU Nordmeyer, A TI Open Source und Kartellrecht SO JIPITEC PY 2010 BP 19 EP 33 VL 1 IS 1 AB „Open source and European antitrust laws: An analysis of copyleft and the prohibition ofsoftware license fees on the basis of art. 101 TFEU and the block exemptions“Open source software and open source licenses (like the GNU GPL) are not only relevant for computernerds or activists – they are already business. They are for example the fundament of LINUX, the onlyreal rival of MICROSOFT’s WINDOWS-line in the field of operating systems for IBM PC compatibles.Art. 101 TFEU (like the identical predecessor art. 81 TEC) as part of the EU antitrust laws prohibitscontract terms like price fixing and some forms of technology control. Are copyleft – the „viral effect“, the„cancer“ – and the interdiction of software license fees in the cross hairs of this legal rule? On the otherside the European Union has since 2004 a new Technology Transfer Block Exemption with softwarelicense agreements for the first time in its scope: a safe harbour and a dry place under a umbrella foropen source software?After the introduction (A) with a description of open source software the following text analyses thesystem of the European Unions competition law respectivley antitrust law and the requirements of theblock exemptions (B). Starting point of antitrust analysis are undertakings – but who are the untertakings(C) in the field of widespread, independent developers as part of the „bazar organization“? To see howmuch open source has to fear from the law of the European Union, at the end the anti competitive andpro competitive effects of open source are totalized within the legal framework (D). The conclusion (E)shows: not nothing, but not much. ER