The rule, precisely
Under Wis. Stat. § 895.045(1), a plaintiff's negligence is measured separately against the negligence of each person found to be causally negligent — not against a single combined total of every defendant's fault added together. In a case with multiple defendants, this means running the 51% comparison once for each one.
A real case decided on exactly this point
The Wisconsin Supreme Court has directly applied this rule in a real case, concluding that summary judgment in favor of one specific defendant was proper because the plaintiff's negligence exceeded that particular defendant's negligence as a matter of law. The court didn't need to look at the plaintiff's fault relative to anyone else in the case — the comparison against that one defendant was decisive on its own.
Barred against one, free to recover from another
Because the comparison happens defendant by defendant, being barred against a less-negligent defendant doesn't affect a plaintiff's ability to recover from a different, more-negligent co-defendant in the very same lawsuit. A plaintiff could walk away from one defendant with nothing while still recovering a meaningful amount from another.
A narrow carve-out: product liability
This per-defendant negligence comparison doesn't apply to strict product liability claims. There, the plaintiff's own negligence is instead compared with the product's defectiveness, under a separate statutory framework specific to that type of claim.
Who applies this rule in practice
Wisconsin uses special verdicts, meaning the jury must answer specific questions and calculate percentages for every party found to be causally negligent — including, where relevant, running the comparison against each defendant separately as the statute requires. See our Wisconsin comparative negligence calculator to see how the outcome shifts right around the 50/51 line for a given defendant.