In Hana Financial v. Hana Bank (decision available here), the Supreme Court took up the issue of whether trademark “tacking” is for the judge or the jury to decide. The Supreme Court found that it was for the jury, not a judge:
Rights in a trademark are determined by the date of the mark’s first use in commerce. The party who first uses a mark in commerce is said to have priority over other users. Recognizing that trademark users ought to be permitted to make certain modifications to their marks over time without losing priority, lower courts have provided that, in limited circumstances, a party may clothe a new mark with the priority position of an older mark. This doctrine is called “tacking,” and lower courts have found tacking to be available when the original and revised marks are “legal equivalents” in that they create the same, continuing commercial impression. The question presented here is whether a judge or a jury should determine whether tacking is available in a given case. Because the tacking inquiry operates from the perspective of an ordinary purchaser or consumer, we hold that a jury should make this determination.