The filing states that certain Ring 4 production cohorts, meaning specific manufacturing batches built during a defined window, experienced battery performance problems, according to iDevice, which reported on the disclosure last week. It identifies certain production cohorts without identifying which ones.

Oura attributes the broader warranty cost increase to earlier design, manufacturing, and supplier-related factors, and says it has since expanded testing and quality control, Android Authority reported. That is a company describing a problem it says it has already moved past. It's also a company that, in a legal filing tied to a stock offering, chose its words carefully enough to avoid naming names.

Worth noting: this is not necessarily the first time Oura has acknowledged battery trouble publicly. Reddit threads and support interactions have surfaced complaints for at least a year, according to Android Police. What's new is the dollar figure and the fact that it now sits inside a document filed with securities regulators rather than a support forum. Prospectus disclosures exist to inform prospective investors, and they carry legal consequences if a company misstates them, which is a different kind of accountability than a customer service reply.

The $84.4 million rise in warranty expense during fiscal 2025 is not attributed solely to Ring 4 batteries. Oura describes it as multi-causal, with battery problems among the contributing factors rather than the whole story, Android Authority reported. The filing does not break out how much of that figure traces back to batteries specifically.

Context helps explain why a hardware defect shows up in the accounts at all. In the nine months ending June 30, 2026, Oura reported $1.21 billion in revenue, up 74% year over year, sold 3.1 million rings, and grew to five million paying members, according to iDevice. Net income climbed from $1.6 million to $60.8 million over the same period, and membership revenue rose 121% to $240.5 million at an 89% gross margin, per the same report.

Hardware still accounts for roughly 80% of Oura's revenue, iDevice reported, which is why a manufacturing fault lands in the financials even while the subscription business is thriving. Oura's filing also includes standard forward-looking risk language warning that current or future ring generations could encounter other quality issues, the kind of boilerplate that shows up in most prospectuses and shouldn't be read as a fresh admission.

Oura replaced affected Ring 4 units free of charge, including some units that had already aged past the standard one-year limited warranty, Android Authority reported. That is a meaningful departure from the company's written terms, which promise one year of coverage, longer only where local law requires it, according to iDevice.

Neither the filing nor the reporting around it specifies affected serial numbers, ring sizes, purchase windows, or the total number of replacements issued. That leaves owners with no published way to confirm whether they qualify, based on the same two reports. Oura has not promised every affected owner the same treatment, and nothing in the filing suggests a formal, universal replacement program exists.

There is at least one documented example of the company acting quickly outside any formal process. An Android Police writer reported in December that Oura's in-app assistant flagged a Ring 4 lasting less than a day and that customer service followed up with a replacement offer, without any prompting from the user, according to Android Police. That is one person's experience, not evidence of a company-wide policy, but it does suggest Oura's internal support process may be more responsive than its published warranty terms imply.

Oura's own benchmark, based on controlled testing of new, unworn rings in sizes 8 through 10, puts expected battery life at 5 to 8 days per charge under typical use with Blood Oxygen Sensing turned off, according to Oura's support documentation, last updated in July. Leaving that sensor on can shorten battery life by up to two days depending on sleep duration, and Oura says real-world use since launch has held close to those lab estimates, per the same source.

A ring lasting well under a day, nowhere near that 5 to 8 day range, is the kind of gap that separates ordinary battery aging from something worth flagging. The Android Police writer who experienced this firsthand said Oura's own app identified the drop before they raised it, and support recommended a replacement without requiring further documentation, according to Android Police.

Rapid battery drain is not the same problem as the overheating incidents that surfaced on Reddit in December, and the two shouldn't be conflated. Posts on the r/OuraRing subreddit around Dec. 5 described Ring 4 units overheating, smoking, and in one case blistering a wearer's finger, along with reports of battery swelling, according to Android Police. A search at the time turned up similar reports of expanding batteries going back roughly a year, per the same report.

An Oura spokesperson told Android Police that the company was reviewing the incidents case by case, including third-party analysis where appropriate, and that based on what it had seen so far, the reports appeared to be isolated rather than part of a broader pattern. Oura also responded directly to affected users on Reddit, offering to investigate individual cases.

Nothing in the SEC filing or in Oura's public statements connects the overheating reports to the battery performance issue described in the warranty disclosure. They may share a root cause in a defective battery cell, or they may not. Right now, they're two separate sets of reports that happen to involve the same product.

Oura has acknowledged, in a securities filing, that certain Ring 4 production batches had battery problems tied to part of an $84.4 million warranty expense increase. What it hasn't said is how many rings were affected, what the failure rate looked like, which serial ranges or sizes are involved, or how many replacements it has issued.

Owners seeing battery life fall well short of the 5 to 8 day benchmark have reason to contact Oura support regardless of warranty status. The company has already made exceptions for units outside the standard coverage window, even without a public policy guaranteeing it will do so for everyone.

The Ring 5 launched in June with redesigned hardware, but nothing in the available reporting confirms whether that redesign addresses the battery problems described in the Ring 4 filing. Oura's IPO paperwork also arrives a few weeks after a proposed class action challenged the 95% sleep accuracy figure the company uses in its marketing, a separate legal matter that shares little with the battery disclosure beyond timing.