Fitbit Surge 2
The Surge's heart-rate monitor tracks your pulse constantly, and sends updates to your phone with only a few seconds' delay. It's also accurate: It measured my average resting heart rate at 60 beats per minute, the same figure I typically get using the traditional finger-on-wrist technique. International Business Times/Nick Deel

San Francisco-based fitness tracker maker Fitbit filed with the U.S. Security and Exchange Comission for a $100 million inital public offering on Thursday. It plans to list on the New York Stock Exchange under the ticker symbol FIT.

Documents filed with the SEC show that the company is substantially profitable, reporting net income of $132 million in 2014. The company generated $745 million in revenue during the same period. The filing was first reported by Bloomberg.

The filing also reveals how many devices Fitbit has sold. The company sold 10.9 million devices in 2014, and has already gotten off to a hot start in 2015, selling 3.9 million devices before March 31.

Fitbit has raised over $80 million in venture capital funding from firms including True Ventures, Foundry Group, and Softbank Capital. Morgan Stanley, Deutsche Bank, and Bank of America Merrill Lynch are the lead underwriters for the IPO. Fitbit says it has no specific plans for the money it will recieve from its offering.

Despite its rosy balance sheet, Fitbit still faces challenges. Many believe that the recently-launched Apple Watch might cut into sales of its fitness trackers, which are generally less full-featured (but also less expensive) than Apple's smartwatch. Fitbit specifically addressed Apple's watch as a potential risk factor in the filing.

You can find Fitbit's S-1 filing here.