Class Action Claims Oura Ring's Sleep Tracking Is Far Less Accurate Than Advertised

A proposed class action filed August 20, 2026 in San Francisco alleges Oura rings cannot directly measure the brain signals that define sleep stages, relying instead on AI estimates from peripheral body signals. The complaint claims Oura advertised 95% accuracy while real results are roughly a coin flip. Oura, which filed confidentially for a US IPO in May 2026, has not commented.