Because they're growing? There are two types of profitability of concern here: 1 - Is the product itself profitable. In this case: does the cost of providing

Because they're growing? There are two types of profitability of concern here: 1 - Is the product itself profitable. In this case: does the cost of providing a payment transaction cost Square more money than they charge for said transaction. A company that fails #1 is a really long way from success. 2 - Is the company itself profitable. You can have #1 but not #2, if you're pouring the bulk of your income into expansion. Square can very well be making money hand over fist, but still be in the red due to pouring all would-be profits into acquiring more market share and R&D into new markets (aka the Amazon model). Naturally, this is a risky move - it presumes that the the core product is long-term sustainable (i.e. the new market share you're acquiring is just as profitable as the market share you already have), and that the new markets you're investing massively in are worth it. All said and done, Square not turning a profit overall doesn't say much about the overall viability of their business model.