Square Inc. shares climbed today after Chief Executive Officer Jack Dorsey said the company is introducing Bitcoin trading for almost all users of its cash payments app, signaling support for the volatile cryptocurrency.

“We support Bitcoin because we see it as a long-term path towards greater financial access for all,” Dorsey wrote in a tweet today. “This is a small step.”

Square shares rose as much as 4.3 percent to $47.50 today in New York. The service will be available to most customers of Square cash, which lets users transfer money to friends and family. Those located in New York, Georgia, Wyoming or Hawaii are excluded.

The company said most of the purchases and sales happen within seconds, and it won’t add an additional percentage or fixed dollar amount onto the sale of Bitcoin. Users can buy as much as $10,000 worth of Bitcoin per week, though there’s no limit to the number of Bitcoins users can sell. One Bitcoin currently trades for about $10,000.

The market for Bitcoin trading platforms is becoming increasingly crowded. Last week, stock-trading app Robinhood said it would roll out free Bitcoin and etherum trading in five states. More than a million people have signed up for “early access” in the few days after the announcement. Square’s service will also compete with Coinbase, the largest U.S. marketplace for trading cryptocurrencies.

Integrating Bitcoin trading into Square’s cash app isn’t without risk. The largest exchanges have suffered from slow trading as demand for crypto has skyrocketed. Coinbase has experienced performance issues, including outages, slow load times and a flash crash in ether, the second most valuable virtual coin.

Square’s move came as some companies have begun to distance themselves from the risky digital-currency market. On Jan. 23, payments startup Stripe Inc. said it would be ending support for Bitcoin payments due to long transaction times and high fees. And social network Facebook Inc. on Tuesday said it would ban ads that promote cryptocurrencies and initial coin offerings.