Whoop, a wearables company, has closed a $55 million Series D round. This brings the company's total funding to more than $100 million. Whoop's raise follows Google's recent $2.1 billion acquisition of Fitbit.  

The company released the Whoop Strap 3.0 earlier this year, and switched from a pay-for-device model ($500) to a membership bundle, including a free device with a monthly fee. The Whoop Strap 3.0 is unique compared to most wearables currently on the market in that it does not have a screen. 

Whoop currently has 11 documents in the Consumer Sleep Technology sector, all in the Data Processing and Analytics category. Apple has 28 documents in the sector, but has yet to implement sleep tracking in the Apple Watch. Amazon has started making a play for the health care industry, and recently purchased Health Navigator. Amazon notably does not currently have any wearable technology. Additionally, Microsoft recently exited the wearable market with the discontinuation of the Band, but remains active in the patent space. Given the recent uptick in market activity in this technology sector, Magic Number is continuing to monitor whether Whoop will fall under the build or buy column in an increasingly competitive landscape.