In August 2009 PatLit asked "When do you sue a holding company?", the question being as to the circumstances -- if any -- in which one should join as a defendant in patent infringement proceedings a company whose only involvement is that it is the holding company for another company which purchased infringing goods from the principal defendant. In the opinion of Mr Justice Floyd (Patents Court, England and Wales) in Fabio Perini SPA v LPC Group Plc & others  EWHC 1929 (Pat), the holding company should not have been joined: the case against it was based only on the fact that the letter from the patent owner (Perini) before action, addressed to LPC Limited (its subsidiary which purchased the infringing goods from the principal defendant, PCMC) elicited a response on LPC Group's notepaper which affirmed "We purchased the equipment from PCMC".
Last Friday, in  EWCA Civ 525, the Court of Appeal dismissed both the appeal and the cross-appeal and affirmed the position taken by the trial judge. Many issues were discussed in the 125 paragraph leading judgment of Lord Neuberger MR -- but this issue was not one of them.