The credit-card company has made an unspecified investment in Square, a two-year-old service that helps businesses and consumers pay with credit cards on a mobile phone or Apple Inc iPhone, both companies said in a statement.
In return, a Visa executive gets to sit on the advisory board at Square, which is also backed by Sequoia Capital and Khosla Ventures.
Square's service employs a miniature magnetic card-reader that plugs into a device, such as an iPhone or Google Android phone. CEO Dorsey in March returned to the microblogging sensation he helped create, taking up the post of executive chairman - in addition to his responsibilities at Square - to oversee product development.