It's high season for initial public offerings (IPOs) -- with more companies going public than ever before last year, a record number of stocks managing to double within their first day of trading, and signs that 2021 will be another huge year for new market entrants. Many recent IPO stocks have posted gains since going public, but investors still have to be selective and focus on high-quality companies in order to maximize long-term returns and avoid getting caught up in hype.

With that in mind, read on for a look at three of the best IPO stocks to buy in March: two that have already gone public, and one that will be making its market debut this month. 

Blocks spelling 'IPO' on top of stacks of coins.

Image source: Getty Images.

Bumble

Love it or hate it, online dating has changed the world of romance. More new love connections are formed through online dating services than at bars, through friends, meeting at the office, or any other channel. Engagement with dating apps will almost certainly continue to grow, and Bumble (NASDAQ:BMBL) is an innovative player in the space that looks poised to be a long-term winner. 

On the Bumble app, women send the first message to men, and the overall user experience is generally tailored toward giving females more control over interactions. Men make up the majority of users and paying customers on most dating apps, and providing an online environment that feels safer and more inviting for women is a hook that should help the company continue to expand its user base and revenue. 

Despite pressure from the coronavirus pandemic, Bumble managed to grow its active user base by roughly 10.9% in the fourth quarter, according to tracking from AppTopia. However, the company is just scratching the surface of its addressable market, and its strong brand and differentiated user experience should help it ride momentum if dating app usage surges in a post-pandemic world. 

Bumble had its IPO on Feb. 11, and recent sell-offs for growth-dependent tech stocks have pushed the stock down roughly 15% from its opening price. There's potential for more volatility in the near term, but this is a stock worth building a long-term relationship with. 

PubMatic

With more business migrating to digital channels courtesy of the e-commerce and streaming revolutions, the digital advertising market still has a long runway for growth. However, rising saturation also means that companies are looking for the most valuable data and most cost-effective way of reaching customers. PubMatic (NASDAQ:PUBM) provides a software platform that analyzes and automates digital advertising purchases, and it stands out as an appealing play in the fast-growing programmatic ad space.

PubMatic completed its IPO in December, and its stock has risen roughly 150% from its $20 per share listing price.  With a market cap of roughly $3.1 billion, it's still a small player compared to specialized competitors like The Trade Desk and Magnite, or digital ad giants Alphabet and Facebook. However, the company is growing at a rapid clip, and its recent successes combined with a promising outlook for the programmatic advertising industry suggests that the business has a long runway for expansion.

PubMatic's sales soared 64% year over year in the quarter, powered by strong demand in mobile, digital video, and over-the-top streaming. Impressive margins also have the company in a good position to post big earnings growth as sales expand. The company notched a gross profit margin of 79.6% in Q4, and net income surged 356% year over year in the period. While earnings can be expected to fluctuate as the company pours resources into strengthening its technology platform and developing new features and service offerings, PubMatic has the potential to be a huge winner over time. 

Roblox

Roblox operates an incredibly popular online gaming platform of the same name. The company is scheduled to have its IPO through a direct listing on March 10, and it will be hitting the market on the New York Stock Exchange under the ticker "RBLX." 

Roblox is more than just a collection of minigames. It's a massive social gaming ecosystem that has the potential to continue evolving as a digital entertainment hub. Players can hop into an expanding variety of games within the broader platform. More technologically adept users can also create their own content and experiences in Roblox, and they can earn money based on the amount of time that other players spend with their content. This dynamic means that the world of Roblox is always growing and evolving, and unique social interactions are a big part of the experience, so there are always new reasons for users to log on.

The company's recently published first-quarter guidance shows that the platform is thriving. Roblox anticipates sales in the first quarter will come in between $320 million and $335 million, good for growth of roughly 102.5% year over year at the midpoint of the target. Daily active users on the company's platform are projected to grow between 59% and 68% year over year, reaching 38.6 million at the midpoint of the target.

Prior to the company's most recent update, management estimated that roughly 75% of U.S. children between the ages of nine and 12 regularly interacted with its platform. Roblox's platform has incredible reach, and there's still huge room for growth as it attracts more users and experiments with monetization opportunities. 

Roblox's last round of private funding valued the company at $32.5 billion, and that hefty sum might raise questions about whether it can live up to that valuation -- particularly in a market that's recently showing more caution toward growth-dependent stocks. Roblox is a risky investment, but there's a lot to like about what the company has built and its stock's prospects after going public.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.