Who is lia­ble for inf­rin­ge­ment of unpu­blished patent applications?

In the case of purcha­se con­tracts, the sel­ler must hand over the item to the buy­er free of mate­ri­al defects and defects in title and must pro­cu­re title. If the item inf­rin­ges the patent of a third par­ty, this is gene­ral­ly to be regard­ed as a defect in title. Sub­se­quent­ly, the buy­er may assert war­ran­ty and dama­ge com­pen­sa­ti­on claims against the sel­ler. In prin­ci­ple, the case is no dif­fe­rent with con­tracts for work and ser­vices (e.g. deve­lo­p­ment con­tracts), to which the state­ments below also apply.

Depen­ding on the indus­try and the natu­re of the pro­ducts, tech­ni­cal pro­gress can be so rapid that new patent appli­ca­ti­ons by com­pe­ti­tors can­not be ruled out in the short term. In such cases, the­re is a risk that a company’s own pro­duct will inf­rin­ge a patent in the future, the appli­ca­ti­on for which alre­a­dy exis­ted at the time of deli­very of the company’s own pro­duct, but was not visi­ble to the sel­ler despi­te patent sear­ches. In prac­ti­ce, this can lead to a dis­pu­te bet­ween the sel­ler and the buy­er about respon­si­bi­li­ty and lia­bi­li­ty if a patent is sub­se­quent­ly gran­ted to a third par­ty and infringed.


When a patent appli­ca­ti­on is filed with the Ger­man Patent and Trade­mark Office (DPMA) or the Euro­pean Patent Office (EPO), the appli­ca­ti­on initi­al­ly remains secret. This appli­es until eit­her the patent is gran­ted and published or 18 months have elap­sed sin­ce the fil­ing date (cf. Artic­le 93(1) EPC or § 31(2) of the Ger­man Patent Act). In the lat­ter case, the patent appli­ca­ti­on is published after the expi­ra­ti­on of the 18 months and can be free­ly view­ed by anyo­ne. In the peri­od bet­ween the patent appli­ca­ti­on and its publi­ca­ti­on, a sel­ler of a pro­duct can­not obtain know­ledge of a patent appli­ca­ti­on and its con­tents even with an exten­si­ve patent search. It is the­r­e­fo­re dif­fi­cult for the sel­ler to design its pro­duct in such a way that the pro­duct does not also inf­rin­ge on as yet unpu­blished patent applications.

Does the inf­rin­ge­ment of unpu­blished patent appli­ca­ti­ons con­sti­tu­te a defect in title?

It has not yet been cla­ri­fied in legal rulings and lite­ra­tu­re whe­ther the inf­rin­ge­ment of an unpu­blished patent appli­ca­ti­on which later leads to the grant of a patent con­sti­tu­tes a defect in title.

An argu­ment against the assump­ti­on of a defect in title is that in the case of a patent appli­ca­ti­on which has not yet been published, neither the pro­tec­ti­ve effects of the patent nor a cla­im to com­pen­sa­ti­on on the part of the patent appli­cant exist and the sel­ler can­not have any know­ledge of an inf­rin­ge­ment until the trans­fer of risk.

Howe­ver, the­re are legal rulings con­cer­ning the law of sales con­tracts accor­ding to which a defect in title exists through rights of third par­ties that beco­me effec­ti­ve after the trans­fer of risk if the­se are roo­ted in sta­tes of affairs that alre­a­dy exis­ted at the time of the trans­fer of risk (e.g. .Fede­ral Supre­me Court, Ruling of 18 Janu­ary 2017 – Case VIII ZR 234/15). Patent appli­ca­ti­ons alre­a­dy exis­ting at the time of the trans­fer of risk can be clas­si­fied as such sta­tes of affairs. If a patent appli­ca­ti­on is sub­se­quent­ly filed, this sug­gests that the inf­rin­ge­ment of a sub­se­quent­ly gran­ted patent con­sti­tu­tes a defect in title.

This impo­ses a con­sidera­ble risk on the sel­ler, which can at least be explai­ned by the fact that the sel­ler, in con­trast to the buy­er, is in a bet­ter posi­ti­on to assess its own pro­ducts and com­pe­ti­tors and may its­elf be able to app­ly for a patent or at least crea­te the con­di­ti­ons for a right of pri­or use (§ 12(1) of the Ger­man Patent Act).


The war­ran­ty and dama­ge com­pen­sa­ti­on claims immi­nent in such a risk can be avo­ided, at least vis-à-vis the purcha­ser, by con­trac­tual­ly sti­pu­la­ting the dis­tri­bu­ti­on of respon­si­bi­li­ty and lia­bi­li­ty for the inf­rin­ge­ment of unpu­blished patent appli­ca­ti­ons. Moreo­ver, if the mat­ter con­cerns inf­rin­ge­ment of unpu­blished patent appli­ca­ti­ons that are based on spe­ci­fi­ca­ti­ons of the purcha­ser (e.g. pro­ducts manu­fac­tu­red accor­ding to the purchaser’s spe­ci­fi­ca­ti­ons), at least in the case of con­tracts for work and ser­vices the seller’s lia­bi­li­ty for such inf­rin­ge­ments may be excluded pur­su­ant to § 645 of the Ger­man Civil Code. Accor­ding to the legal rulings of the Dis­trict Court of Stutt­gart, this prin­ci­ple can also be appli­ed to con­tracts of sale and con­tracts for work and materials.


Risk sha­ring regar­ding unpu­blished patent appli­ca­ti­ons should be con­trac­tual­ly regu­la­ted, to pro­vi­de cla­ri­ty regar­ding respon­si­bi­li­ty and lia­bi­li­ty risks.


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