Jack Dorsey's company is testing support for bitcoin through its Cash payments app.
"We're exploring how Square can make this experience faster and easier, and have rolled out this feature to a small number of Cash app customers," a Square spokesperson said via email to CNBC. "We believe cryptocurrency can greatly impact the ability of individuals to participate in the global financial system and we're excited to learn more here."
The test does not allow individuals or businesses to send or accept bitcoin, Square said.
Shares of Square spiked more than 5 percent Wednesday to a record high as one Wall Street firm was quick to recommend the stock on this potential development. The stock closed up 2.3 percent at $40.66 a share.