Adds details throughout

May 21 (Reuters) - Oura, the maker of smart wearable Oura Ring, said on Thursday it has confidentially filed to go public in the United States.

The U.S. IPO market has bounced back strongly after a brief lull in March, as investors look past geopolitical uncertainty and pour money into new listings.

Elon Musk's SpaceX filed to go public in the U.S. on Wednesday, in what is set to be the largest IPO of all time - potentially opening the door for other companies looking to tap the public markets.

Oura, which was valued at about $11 billion in a funding round in October, makes the Oura Ring that tracks sleep, activity and other health metrics, offering personalized wellness insights and guidance.

The ring is now available in over 4,600 retail locations globally, the company said.

The company, which was founded in Finland over a decade ago, has sold over 5.5 million rings worldwide, according to its website. The ring is not advertised as a medical device.

Oura's growth quadrupled in terms of total revenue over the past two fiscal years, and it has invested its gross profit back into the business.

Earlier this year, Oura announced its partnership as the official wearable of Team USA and LA28 Olympic & Paralympic Games to provide Oura Rings to athletes for performance, recovery and wellness tracking.

Confidential filings with the U.S. securities regulator allow companies to prepare for IPOs away from public market scrutiny.

The number of shares to be offered and the price range for the proposed offering have not yet been determined, Oura said.