Square markets those small white add-ons that you can stick into any iPhone or iPad and instantly turn it into a cash register. They have been a huge hit with small businesses.
Square has been discussing a public stock sale with Goldman Sachs and Morgan Stanley.
Founder Jack Dorsey owns 28.3% of Square, and his stake was already valued at well over $1 billion. In addition, as the founder of Twitter, he owns a stake in that company that is about to become worth up to $679 million.
The WSJ also reported a bunch of financials for Square:
Square is growing nearly as fast as its soon-to-be-public sibling, with sales approaching $1 billion in 2014, according to an internal projection people familiar with the matter shared with the Wall Street Journal. That revenue represents what Square takes from the roughly $30 billion in total transactions it expects to process next year, before it passes much of that amount on to partnering credit card companies.
Sales will be about $550 million this year on total payment volume of around $20 billion, these people said. Roughly 70% to 80% of Square's revenue gets kicked back to credit card companies, putting the company's net revenue closer to $110 million to $165 million.
Though Dorsey has said publicly the company does not turn a profit, he's internally discussed a plan that would make Square profitable in 2015, according to one person familiar with the matter.