In a unanimous decision delivered by Justice Sonia Sotomayor, the Supreme Court held that an invalidity defense must be proven by “clear and convincing evidence,” likely ending Microsoft’s efforts to avoid a $200 million plus damages award.

As previously reported, Microsoft challenged a Federal Circuit Court of Appeals finding of validity in favor of patent holder, i4i, which resulted in an award of well over $200 million in damages to i4i.  In its decision, the Federal Circuit relied on its long standing precedent that patent invalidity must be proven by “clear and convincing evidence.”

Microsoft argued that the Federal Circuit erred in requiring this heightened standard, and urged that the lesser “preponderance of the evidence” standard should apply to determinations of patent invalidity, as is the case in finding patent infringement.  The “preponderance of the evidence” standard applies in most civil actions and essentially requires a finding that it is “more likely than not” that the evidence presented is true, whereas the higher “clear and convincing” standard requires a “substantially more likely than not” or “highly probable” finding.

The Supreme Court was not swayed, stating that: “We consider whether §282 requires an invalidity defense to be proved by clear and convincing evidence. We hold that it does.”

For the complete Supreme Court Opinion click here.