Inc on Thursday said it would buy primary healthcare provider One Medical for $3.49 billion in an all-cash transaction, sending shares of the online retailer up about 1% in premarket trading.

The deal heralds a dramatic expansion of Amazon's push into healthcare, having piloted virtual care visits for Amazon employees in Seattle in 2019 before offering such services to other employers and in other cities under the Amazon Care brand.

"We think healthcare is high on the list of experiences that need reinvention," said Neil Lindsay, senior vice president of Amazon Health Services.

The e-commerce giant agreed to pay $18 for each share of One Medical, representing a premium of 76.8% relative to the healthcare firm's closing price on Wednesday.

The news knocked down the stock of telehealth leader Teladoc Health Inc by 6% in premarket trading. Shares of drugstore retailers CVS Health and Walgreens Boots Alliance fell over 2% before the bell.

In One Medical, Amazon is aiming to acquire a company with brand-name customers such as Airbnb Inc and Alphabet Inc's Google, according to its website.

Amazon Care itself picked up Hilton Worldwide Holdings Inc in a deal announced last year. Until now, the retailing giant has partnered with a different company called Care Medical, focused on serving Amazon Care users, to enable house calls in places such as the Washington-Baltimore metro area.

The deal is subject to approval by One Medical shareholders as well as regulators. It was not immediately clear if the agreement posed antitrust concerns.

(Reporting by Manas Mishra in Bengaluru and Jeffrey Dastin in New York, Editing by David Goodman and Bernadette Baum)