If you're looking to double your money over the next few years, looking for stocks that are involved in e-commerce is a good bet. The COVID-19 pandemic has changed consumer behavior and accelerated online shopping trends. 

Two e-commerce stocks that have the potential for significant upside are Stitch Fix (NASDAQ:SFIX) and Sea Limited (NYSE:SE). Here's why these stocks could double your money.

A hand drawing a red line pointing upward.

Image source: Getty Images.

Stitch Fix: The online personal styling service

Stitch Fix has experienced substantial growth over the last several years. Revenue increased from $342 million in fiscal 2015 to $1.58 billion in fiscal 2019, but its addressable market is massive at $400 billion. Stitch Fix ended the last quarter with 3.4 million active clients who provide valuable data and feedback to the company regarding their likes and dislikes. Over time, this helps the service grow increasingly accurate with its style recommendations. 

The COVID-19 outbreak caused Stitch Fix to shut down three distribution centers during the last quarter, and that slowed down its sales growth dramatically. Revenue fell 9.1% year over year in the fiscal third quarter, but that was a temporary speed bump. Active clients increased 9.1% year over year, and merchandise revenue showed meaningful improvement week to week through April. 

Looking ahead, Stitch Fix is preparing to begin using its direct buy service to acquire new clients, which could be a significant growth driver over the next few years. Direct buy allows existing customers to purchase specific items tailored to their tastes directly from Stitch Fix. Direct buy's penetration was only 13% of women clients in May, but the growth of the service has looked very promising.

Direct buy revenue more than tripled quarter over quarter, and management has found these purchases to be highly incremental to customers' regular Fixes. This means direct buy could meaningfully increase revenue per client, which explains why management wants to use the service to lure in new shoppers.

Stitch Fix is helping customers save time, which is its main value proposition. The service narrows tens of thousands of items down to a few dozen shoppable pieces based on client feedback. With a market cap of just $2.3 billion, this stock has a lot of room to climb with such a large market in front of the business. 

A computer keyboard with icons of a shopping cart, delivery truck, and a credit card shown on the keys.

Image source: Getty Images.

Sea Limited: The top e-commerce and gaming provider in Southeast Asia

Sea Limited operates the No. 1 online gaming and e-commerce platform in Southeast Asia and Taiwan. This region provides a long runway of growth with 600 million people and rising per capita GDP. Sea's latest numbers show why it's a stock that could easily double your money. 

In the first quarter, total adjusted revenue increased 58% year over year to $914 million. Sea's digital entertainment business, which includes results from the popular mobile game Free Fire, grew adjusted revenue 30%, driven by a 48% increase in quarterly active users and a 73% increase in paying users. Sea's Shopee e-commerce platform was also clicking on all cylinders with adjusted revenue more than doubling year over year. 

Demand for online games and shopping has accelerated during the pandemic. CEO Forrest Li called it a "step change" in the global growth of the digital economy. The record quarter that Free Fire experienced in engagement carried over to the second quarter, and management cited a similar trend taking shape with e-commerce. The number of gross orders on Shopee increased by 111% year over year and accelerated in April to 140% growth, continuing the momentum into the second quarter. 

Most importantly, as Shopee grows larger, top consumer brands are starting to expand their partnerships with Sea as Procter & Gamble did recently. Deepening relationships with big brands will help cement Sea's leadership in e-commerce in the markets where it operates. 

The stock has climbed over 200% year to date. Investors might be hesitant to chase that kind of performance, but keep in mind that Sea is still a relatively small business with just $2.54 billion in trailing 12-month sales. The stock is richly valued at 22.7 times revenue, but with robust growth that is accelerating as more people migrate online, this growth stock could double again over the next three to five years.