Sean P. McMahon
Sean P. McMahon is a USPTO correspondent of record based in Mankato, MINNESOTA, listed on 741 trademark filings (593 currently live). The correspondent has worked across 221 distinct trademark owners — a mid-breadth client roster at roughly 3.4 marks per client. In TTAB matters, 80 proceedings appear on the record, more often as defendant (41) than plaintiff (39). The correspondent is associated with Sean P. McMahon, PLLC.
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Explore the Trademark Intelligence Library
Editorial deep dives on prosecution strategy, TTAB, and brand portfolios
TTAB Q4 2025: Opposition Plaintiffs Won Roughly Five of Every Eight Decisions
When the Trademark Trial and Appeal Board cleared its opposition docket in Q4 2025, the people who filed the oppositions mostly walked away winners.
Maradona's Heirs Win at the TTAB as Q1 Filings Slip 7.4%
On the last day of the quarter, the Trademark Trial and Appeal Board sustained an opposition brought by the heirs of Diego Armando Maradona against Sattvica S.A.
Challengers Won Most TTAB Oppositions in Q3 2025 — and Big Tech Filed a Late-September Wall of Them
When the Trademark Trial and Appeal Board decided an opposition on the merits this quarter, the party bringing the challenge usually won.