Company will let customers buy cryptocurrencies and use them for online purchases
Those virtual coins could then be used to buy things from the 26 million sellers which accept PayPal, it said.
PayPal plans to roll out buying options in the US over the next few weeks, with the full rollout due early next year.
Bitcoin prices rose alongside the news, breaking the $12,000 (£9,170) mark.
The other cryptocurrencies to be added first will be Ethereum, Litecoin, and Bitcoin Cash (a spin-off from Bitcoin).
All could be stored “directly within the PayPal digital wallet”, the company said.
Cryptocurrencies have remained a niche payment method, partly down to the rapid change in prices they can experience compared with traditional state-backed currencies. That has made them popular among some types of investors.
PayPal said it was aiming “to increase consumer understanding and adoption of cryptocurrency”.
“As part of this offering, PayPal will provide account holders with educational content to help them understand the cryptocurrency ecosystem,” it said.
PayPal Holdings Inc. plans to allow customers to buy cryptocurrency through their accounts and use cryptocurrency for merchant payments, a move that helped power its stock to a record high in Wednesday trading.
The company announced Wednesday morning that it is introducing a way for customers to buy, hold and sell certain cryptocurrencies within the PayPal PYPL wallet. This will roll out over the coming weeks in the U.S.
The announcement helped send PayPal shares surging 5.5% in the session. They finished the day at $213.07, above their previous closing high of $210.82 from Sept. 2.
Initially, PayPal users will be able to buy Bitcoin BTCUSD , Ethereum ETHUSD , Bitcoin Cash BCHUSD , and Litecoin LTCUSD through this new capability. PayPal intends to bring the function to its Venmo platform and to certain international markets in the first half of next year.
But David Gerard, author of Attack of the 50 Foot Blockchain and the forthcoming Libra Shrugged: How Facebook Tried to Take Over the Money, said PayPal was describing “a crypto day-trading market”.
“I’m at a loss as to who the market is for PayPal as a crypto-exchange,” he said.
He likened it to playing the stock market, but with Bitcoin – whose volatile and less well-regulated nature was like “gambling on penny stocks”.
“Have a flutter, drop $10 on it, you’ll learn things you wouldn’t learn any other way – but you are gambling,” he warned.
He said there were “a lot of big players who manipulate the price”, and ordinary people risked losing their money.
“I don’t expect much of a market for this beyond existing crypto holders… I’m baffled that PayPal would offer this, and it’s not clear what they’re trying to do here,” he said.
“There must be someone at PayPal who is very interested in cryptocurrencies,” he added.
Paying with crypto
Other payment firms, such as Square’s Cash app and Revolut, have already offered cryptocurrencies for sale. But PayPal has one of the largest merchant networks in the world.
When it comes to using the virtual coins, PayPal will convert the cryptocurrency into the relevant national currency, so the company being paid will never receive the virtual coins – just the correct amount of pounds or dollars.