Finnish wearables maker Oura has filed to go public, revealing rapid growth just as a wave of rivals steps up efforts to challenge its dominance of the smart ring market. The filing shows a company at the height of its commercial success, but it comes amid intensifying competition from companies including France's Circular, China's RingConn and India's Ultrahuman, each pursuing different features to differentiate their products, from payment functionality to on-device software.

Oura filed to go public on 3 September, reporting revenue that nearly doubled to $1.21 billion for the nine months to 30 June, with 3.6 million rings sold over the past year and around five million paid members. The filing follows the recent launch of the Oura Ring 5. Rivals are pushing in varied directions: Circular's upcoming Ring 3 will support tap-to-pay via NFC, RingConn has added haptic vibrations, and Ultrahuman, which raised $70 million backed by Qualcomm's venture arm, aims to run software directly on its rings for AI interactions and gaming, having redesigned its device after losing a US patent dispute to Oura. Other entrants, such as the Pebble Halo and Dreame Ring, are introducing screens and touchpads, prompting concerns that smart rings could lose the minimal, screen-free appeal that first made them popular.