Mark A. Borsos

I'll research this attorney before writing.

Mark A. Borsos — Partner, Fitch, Even, Tabin & Flannery LLP (Chicago)

Focus areas. Borsos is a generalist IP litigator and prosecutor rather than a single-technology specialist. His firm bio lists medical devices and therapies (orthopedic implants, cardiac stimulation devices, wound-healing compositions), biotechnology and gene therapy, printers and ink cartridges, semiconductors and fabrication, chemistry/polymers, construction products, food processing and packaging, lighting, security/encryption, and automotive components. His tracked litigation docket, however, is concentrated entirely in one technology: inkjet printing hardware (printhead heater chips, thermal sensing and bondpad/power-routing patents). Prosecution-side work has included reissue applications and a book chapter on patent protection strategy in early drug development.

Side preference. The tracked docket shows a 6/6 plaintiff-defendant split across 12 entries, but that split is a caption artifact rather than evidence of adverse-side experience: every one of the 12 entries arises from the same dispute family, Slingshot Printing LLC v. Canon U.S.A., Inc. / Canon U.S.A., Inc. v. Slingshot Printing LLC. The district court filings in the Eastern District of New York caption Slingshot as plaintiff, while the parallel PTAB proceedings caption Canon as petitioner and Slingshot as patent owner — the same representation recorded under two party orderings. In every appearance I could verify independently (Law360, Federal Circuit opinions, PTAB filings), Borsos acted for Slingshot, a Delaware licensing entity holding former Lexmark inkjet patents acquired via Funai. On this record, his patent litigation practice is patent-owner/NPE-side enforcement work, not operating-company defense; the data does not support a claim that he regularly defends accused infringers in patent cases (his firm bio does describe defense-side work in trademark and trade dress matters).

Firm context. Borsos has spent his entire legal career at Fitch Even, the Chicago IP boutique founded in 1859, joining in 2002 and now a partner. No prior firm appears in public records. He works the Slingshot matters alongside MoloLamken (Rayiner Hashem, Kayvon Ghayoumi, and others) under the two firms' strategic alliance, with Fitch Even supplying the Chicago-based patent-side bench (Paul Henkelmann, Timothy Maloney).

Notable matters, PTAB/IPR, and credentials. The Slingshot v. Canon campaign is his most prominent tracked work and has gone poorly for his client: after Canon petitioned for IPR on the asserted patents, the PTAB found all challenged claims unpatentable, the two E.D.N.Y. district court cases (Nos. 22-cv-00123 and 22-cv-01852) were stayed pending those reviews, and the Federal Circuit affirmed the Board in a series of nonprecedential rulings — No. 24-1956 (U.S. Pat. 7,195,341, Apr. 2026), a Rule 36 judgment in No. 24-2132, Nos. 25-1032/25-1033 (U.S. Pats. 7,290,864, 7,484,823, 7,594,708, July 16, 2026), and No. 24-2127 (U.S. Pat. 7,152,951, July 21, 2026). Borsos is named on the Federal Circuit briefs and signed the patent owner's notices of appeal (e.g., IPR2023-00313), and he is a regular PTAB practitioner — his firm bio describes a "unique focus" on post-grant proceedings including reissue, reexamination, and IPR, and he co-presented a 2025 webinar on IPR's downstream effects on parallel litigation with MoloLamken. Earlier representative matters include patent and license litigation over cardiac stimulation reissue patents for a Fortune 500 client, interspinous implant and orthopedic screw suits for medical device companies, and liquid-egg processing patent litigation for a food processor. Bar/education: J.D., University of Michigan Law School (2002); B.S. Biology, University of Michigan (1999); admitted in Illinois, before the USPTO (Reg. No. 50,479), the Federal Circuit, the Fourth Circuit, and the N.D. Ill., W.D. Mich., and E.D. Mich. district courts.