(Bloomberg) — Square Inc., the mobile-payments company founded and led by Jack Dorsey, the interim chief executive officer of Twitter Inc., filed confidentially for an initial public offering, people with knowledge of the matter said.

The people asked not to be identified because the information is private.

Square, which processed $30 billion in payments from its millions of merchant customers in 2014, has been expanding into other areas such as business lending and payroll processing to provide more services.

Aaron Zamost, a spokesman for San Francisco-based Square, declined to comment.

Under the Jumpstart Our Business Startups Act, companies with less than $1 billion in revenue can file for an IPO with the U.S. Securities and Exchange Commission privately and work out the details with the SEC outside the public eye.

In May, Square announced a $25 million funding round from Victory Park Capital specifically for itsSquare Capital business lending program. Square Capital offers loans to merchants that are repaid through a portion of sales processed by Square.

In June, Square released a payroll processing service for merchants in California, which the company said it will bring to additional states soon. Also in June, Square unveiled a wireless device that enables merchants to accept payments from Apple Pay through a smartphone or tablet.

Forbes reported last month that Square is preparing to file for an IPO, citing unnamed sources.

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