I heard that phrase—“Square is a beast”—two years ago from a venture capitalist who invests in payments and fintech firms. He was sure Jack Dorsey’s other company (Dorsey is better known as the CEO of Twitter) was on its way to becoming a financial behemoth.

I thought of the VC’s remark on September 15 when Square announced a new line of payroll services that will let companies pay their workers through Square, and let workers get paycheck advances of up to $200. Those arrangements offer businesses more flexibility with their capital. They will also let workers get paid quicker, since payroll arrangements will not have to rely on the conventional banking system, where payments take days to process.

The key to all this is Cash App. Launched in 2013, Cash App began life as a Venmo-like app to transfer money among friends. The millennial money-mover has since evolved into a full-blown banking service that offers direct deposit, debit cards and more. The app has also turned into a cash machine for the company, earning $281 million in gross profit for Square last quarter while it grew to 30 million users.

By adapting Cash App to provide payroll services, Square is poised to muscle onto the turf of ADP and other HR giants. In the longer term, it could use the app to move into fields like tax or investment advice. Cash App already offers tools to buy stocks and cryptocurrency.

Meanwhile, Square has already built up a healthy business providing loans to its business customers—letting them borrow against the sales that come in through payments on its growing array of hardware terminals. (Did you know Square sells $800 cash registers?)

These are huge advances for a company that made its name helping farmers' market vendors accept card payments via their iPhones. From this early niche, Square built out a business that now resembles Apple’s multi-tentacled eco-system—one that uses a piece of hardware to lock customers into an array of other products and services. On top of all this, the company is benefiting from consumers’ growing aversion to cash in the pandemic era. Little wonder Square’s share price has climbed 150% this year.

Square’s emerging financial fortress is far from secure though. The company is not the only one that wants to parlay a cash transfer app into a banking empire—PayPal is rushing to do the same with its Venmo app. Meanwhile, quiet giant Shopify is leveraging its website-as-a-service business to offer financial products to its millions of merchant customers. And tech giants Apple and Google have payments empires of their own, which they could adapt to poach customers from Square.

But none of these rivals currently possess a two-sided payments business—providing banking-like services to both consumers and businesses—on the scale of Square. That’s why, for now, the company is the beast to beat.