A federal appeals court on Thursday reversed a lower court ruling in favor of American International Group Inc. in a decades-old trademark dispute with a small, similarly named insurance agency.

Maryland Heights, Missouri-based A.I.G. Agency Inc. allegedly began calling itself “AIG” around 1958, while AIG was incorporated in 1967 and first began using the “AIG” trademark sometime between 1968 and 1970, according to the ruling by the 8th U.S. Circuit Court of Appeals in St. Louis in A.I.G. Agency, Inc. v. American International Group, Inc., doing business as AIG.

AIG obtained a federal trademarked registration for “AIG” in 1981 that is still active, according to the ruling.

AIG began communicating with A.I.G. in 1995, notifying it of its trademark registration and demanding it stop using “AIG” because “it was likely to confuse consumers.”

A.I.G.’s attorney responded it had the right to use the name in Missouri and Illinois because it had been doing so in those states before AIG registered its trademark.

A.I.G. sued AIG in 2017, charging trademark infringement and unfair competition and violation of the Lanham Act, the federal statute that governs trademarks, service marks and unfair competition.

The U.S. District Court in St. Louis granted AIG summary judgment in the case, and was overturned by a unanimous three-judge appeals court panel.

In overturning the lower court, the court cited a legal doctrine which bars trademark infringement claims when there has been an unreasonable delay in making them.

The court failed to conduct a meaningful analysis of when AIG’s alleged infringement became actionable, the ruling said. “The district court did not announce any test on which it relied for determining when a likelihood of confusion rose” as to the similarity in names it said.

“It also did not meaningfully analyze the strength of (AIG’s) mark at the relevant times, whether (A.I.G.) intended to confuse the public, the degree of care expected of potential customers, or the evidence of actual confusion,” the ruling said, in overturning the lower court ruling and returning the case to the court.

Attorneys in the case did not respond to requests for comment.

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