Wis. Alumni Rsch. Found. v. Apple Inc

Authored by: Jeremy J. Gustrowsky

A recent Federal Circuit decision highlights how strategic decisions in patent litigation can have long-lasting consequences. The Wisconsin Alumni Research Foundation (WARF) spent over a decade pursuing Apple Inc. for allegedly infringing U.S. Patent No. 5,781,752, which covers a “Table Based Data Speculation Circuit for Parallel Processing Computer.” WARF first accused Apple’s A7 and A8 processors of infringement, and later, in a separate lawsuit, targeted Apple’s next-generation A9 and A10 chips.

Initially, WARF argued both literal infringement and infringement under the “doctrine of equivalents” (a legal theory that allows a patent owner to claim infringement even if the accused product doesn’t match the patent’s claims exactly, but is close enough in function and result). However, before trial, WARF made a tactical decision: it agreed to drop its doctrine of equivalents argument in exchange for Apple not introducing certain evidence at trial. WARF proceeded only on literal infringement and won at trial, but the verdict was later overturned on appeal because Apple’s products did not literally infringe under the correct interpretation of the patent.

After losing on literal infringement, WARF tried to revive its doctrine of equivalents argument—first for the original chips, then for the newer ones in a second lawsuit. The courts refused, finding that WARF had intentionally abandoned this theory in the first case and could not bring it back later. The Federal Circuit emphasized that once a party waives a legal argument for strategic reasons, it cannot get a second chance in a new lawsuit involving essentially the same products and patent. The court also applied the “Kessler doctrine,” which protects a company from repeated lawsuits over the same products once a court has found them non-infringing.

This case serves as a cautionary tale for patent owners: choices made during litigation—especially about which infringement theories to pursue—can close the door on future claims, even as new product generations are released. Once a court has decided that a product does not infringe, the patent owner cannot simply repackage and refile what is essentially the same dispute over the same products and patents.