Federal Circuit revives Sonos v. Google: laches allowed in rare cases only

Context: Sonos and Google have been locked in a patent infringement dispute since January 2020, when the former sued the latter over two patents related to smart-speaker multi-room and volume-grouping tech in both the United States International Trade Commission (ITC) and the Western District of Texas. That same year, Google filed a countersuit and a declaratory judgment of non-infringement in the Northern District of California, where the district cases were then consolidated. Between 2022 and 2023, the ITC ruled in favor of Sonos, issuing an import ban on Google’s smart speakers, Chromecast, and Pixel phones, and the Northern District of California jury awarded Sonos $32.5 million in infringement damages. But those decisions were quickly backtracked when Judge William Alsup of the same court quashed the jury verdict, finding the patents unenforceable, and the United States Court of Appeals for the Federal Circuit then allowed newer, modified versions of Google’s devices to be imported. Sonos appealed Judge Alsup’s ruling, arguing that the district court:

• erred in granting judgment of invalidity of two of the patents; and
• abused its discretion in holding those same two patents unenforceable due to prosecution laches (a doctrine which defendants invoke to assert that the claimant has delayed in asserting its rights, making it unfair for the court to give relief).

What’s new: In an opinion handed down yesterday, the Federal Circuit partly-reversed and partly-affirmed the lower court’s decision, most notably throwing out its finding of prosecution laches and reiterating that laches is an equitable defense reserved for rare cases (August 28, 2025 Federal Circuit opinion). It held that the district court had abused its discretion in finding that Google was prejudiced by Sonos’ alleged delay in claiming the subject matter at issue via continuation practice.

Direct impact: This is a huge win for Sonos as it restores the enforceability of Sonos’ invalidated patents, and reinstates the jury’s $32.5 million verdict against Google (or allows for Sonos to settle and strike a licensing deal). While Google has already started rolling features back into its redesigned products, this decision may mean it faces restrictions or invalidation requirements once again.

Wider ramifications: This case has huge consequences for cases where defendants may want to invoke laches based on continuation applications – especially where they argue that the patent owner could have filed the claims earlier. The failure to assert a claim in a timely manner can result in that claim being barred by laches, but delay alone is not enough to prevent a claim from obtaining relief: it is up to the defendant to prove why that delay makes it unfair for the court to give relief, including a showing of prejudice to the accused infringer. The Federal Circuit ruled that Google failed to meet the burden of proof. And, it found, even though the claims were continued over more than a decade, this did not constitute enough “egregious misuse” to trigger laches.