Google on Friday said it is buying Fitbit for $2.1 billion, hopping into the fitness and wearables scrum dominated by competitors like Apple.

The Mountain View, California-based company is moving back into the fitness sector after previous attempts in wearables failed to take off. Google has yet to release an actual smartwatch device, but its Android operating system for smartwatches called WearOS lags behind similar offerings from Fitbit, Fossil and Samsung. Other stabs at wearables, like Google Glass, have also flopped.

Fitbit pioneered, and once dominated, the fitness tracker space, but it has since lost market share. The company's market capitalization soared to nearly $10 billion after becoming a public company in 2015. But it has since declined to well below $2 billion this week.

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The two companies are hoping that Google's scale and Fitbit's expertise in wearables will give them an edge against the competition, namely Apple, which has been growing its revenues because of its wearables category. Fitbit has sold more than 100 million devices and is available on both Android and iOS platforms.

"With Google's resources and global platform, Fitbit will be able to accelerate innovation in the wearables category, scale faster, and make health even more accessible to everyone," Fitbit co-founder and CEO James Park said in a statement.

Other internet companies have also signaled an interest in expanding into wearables. According to The Information, which cited two sources familiar with the matter, Facebook also considered purchasing Fitbit, though for roughly half the price that Google paid for the company.

Wall Street not impressed

Some Wall Street analysts were skeptical on the acquisition. "Google is uniformly bad at consumer products in our view," Wedbush analysts said in a research note. "We expect a Google-controlled Fitbit to remain entrenched well behind Apple's watches and other inexpensive competitive products," they added.

Regardless, Fitbit shares soared 15% on the news in Friday trading to about $7.15 per share. Google's stock price notched upward 1% to about $1,269 per share.

The tech giant paid $7.35 per share in cash, or the steep price tag of $2.1 billion, for the fitness wearable company. That's peanuts for Google's parent company Alphabet, which as of September had about $121 billion in cash and securities on hand. Google is expected to close the transaction sometime next year.

Google's privacy pledge

In a blog post, Google also addressed data privacy concerns for consumers. The tech giant, which has been racked by several data privacy scandals, said health and wellness information will never be sold to advertisers.

"Fitbit health and wellness data will not be used for Google ads," Rick Osterlohm, senior vice president of devices and services, wrote. "And we will give Fitbit users the choice to review, move, or delete their data."

Fitbit said its privacy and security guidelines won't change and that it will continue to be transparent about the data it collects. The company says it collects data including a user's date of birth, gender, height and weight, while for some users it also stores logs tracking their food and water intake, as well as sleep and female health patterns.

— The Associated Press contributed reporting.