lt's been four years since Square (NYSE:SQ) went public, and early investors are sitting pretty right now. The payments processor and cottage industry enabler hit the market at $9 in mid-November 2015, and $1,000 invested in Square stock at the time of its IPO would be worth $7,527 today.

A seven-bagger is a pretty good haul, and some investors are faring even better. Square wasn't always a winning IPO. By early 2016 it buckled below its original $9 price tag, bottoming out at $8.06 three months after its Wall Street debut. The shares would be an eight-bagger for the opportunistic investors who bought into the stock in early 2016.

A cashier rings up a customer at a bike shop using Square as a point-of-sale.

Image source: Square.

Square meal

Square's hardware and software platform that allows anyone with a smartphone to process digital payments keeps gaining traction. Square served as the middleman for a record $28.2 billion in transactions in its latest quarter, a 25% gain over the past year, but revenue is growing even faster. Adjusted revenue and EBITDA rose 40% and 85%, respectively, as the high-tech financial services provider beefs up its ecosystem.

Over the past few years Square has gotten people to buy into its free or nearly free credit card readers that seamlessly plug into smartphones. Its hardware has beefed up lately, with Square Terminal and Square Register rolling out over the past two years as turnkey point-of-sale solutions. It's a brilliant plan. Square gadgets are Trojan horses, and I mean that in the best of ways since now it's making it easier for Square to break into everything from payroll and gift cards to small-business loan financing. Square's Cash app playing nice with bitcoin now makes it one of the largest and most successful cryptocurrency stocks.

The end result of Square's business is a dynamic player that is taking on larger players in tech and finance and still expanding its reach. The company's revenue actually accelerated for eight consecutive quarters before that streak came to an end earlier this year. And Square is still innovating. It now has 20 different seller-facing products, and it's just scratching the surface.

The stock itself isn't cheap, and that's the only thing that may keep Square from being a seven-bagger through the four years. The stock is fetching nearly 70 times forward earnings, and a trailing revenue multiple approaching seven. These aren't cheap multiples, but Square's ability to innovate its way to unexpected growth makes it a stock worth owning. The past has been great. The future is still bright.