What happened

The stock market gave back some of Monday's gains on Tuesday, but if you looked at a quote of Square's (NYSE:SQ) stock price, you'd never know it.

As of 10:40 a.m. EDT, Square's stock was trading for almost $129 per share -- a gain of more than 8% on the day and a fresh all-time high.

Square Register POS terminal

Image source: Square.

So what

Today's move is just the latest in a sustained upward trend for the fintech stock. Square has gained 24% over the past week alone and 43% in the last month; it has more than doubled so far in 2020.

SQ Chart

SQ data by YCharts

In short, the COVID-19 pandemic seems to have accelerated the growth of cashless payments in brick-and-mortar retail stores, as well as among individuals. Square has done an excellent job of helping its merchants build out things like curbside service and online stores, and the company recently rolled out on-demand delivery service to Square Online Store sellers.

Square also has received some major analyst upgrades recently, which don't affect the business itself but have certainly helped to fuel the rally.

Now what

Square was already a pretty expensive stock by most valuation metrics before the recent rally, and that's especially true now. The stock trades for more than 11 times trailing-12-month (TTM) sales, despite not yet having reached consistent profitability. However, the company's opportunity is undeniable. If the Cash App user base keeps growing, Square's product offerings continue to expand, and the company is successful in building out its e-commerce seller base, there could be more upside potential ahead.