Visa Inc., the world’s largest credit- and debit-card company, said Friday it currently has about a 1 percent stake in the mobile-payments firm Square Inc. based on a 2011 investment. Visa told Reuters its current holdings are a little more than 4.19 million shares of Class B common stock.

Visa has the option to convert as many as 3.52 million of these shares into Class A stock, according to a disclosure filed with the U.S. Securities and Exchange Commission Thursday, which would give it at most a 9.99 percent stake in the share class.

If other shareholders also were choose to convert their stock at the same time, then Visa’s stake would be less.

Square, run by Jack Dorsey, who is also CEO of Twitter Inc., conducted an initial public offering in November.

Visa’s about 1 percent stake is based on Square’s fully diluted common equity as of Dec. 31, 2015.