Looking back at the SPAC boom of 2020 and 2021, it shouldn't be too surprising that the mania was unsustainable. There were times when more than 10 blank-check companies went public in a single day, and there are still hundreds of SPACs searching for merger targets.

As the market's appetite for speculation ran out in 2022 due to inflation, recession fears, and more, most ex-SPACs were among the market's hardest-hit stocks. However, there are some that still look like excellent long-term opportunities for patient investors, especially at their current stock prices. Here are two in particular that I own, both of which could have 10-bagger potential if they can execute on their respective opportunities.

Could this company truly disrupt the banking industry?

Banking disruptor SoFi (SOFI -3.17%) is down about 40% from its SPAC valuation ($10 per share in all three of these cases) and is down by more than 75% from its 52-week high.

To be sure, there are a few reasons for the underperformance. For starters, SoFi's original business was student loan refinancing, and it still is a big part of the company. With federal student loans remaining deferred, this part of the business has justifiably performed poorly. Plus, with inflation and recession fears, it's possible that banks will see a general uptick in loan defaults and a drop in consumer demand.

However, SoFi's business continues to grow impressively, and the company seems to be luring customers away from the traditional banks and brokers. SoFi's membership base now sits at 4.3 million, up 69% year over year, and SoFi's financial service products are taking off, especially its SoFi Money (checking/savings) and SoFi Invest (brokerage) platforms. SoFi is profitable on an adjusted basis, and with this kind of growth, a discount of more than 10% to its book value looks extremely compelling.

Is this the most underappreciated social network?

With a market cap of just $1.27 billion, Nextdoor (KIND 2.45%) trades for a much cheaper valuation than most of its social media peers. To put this into perspective, this is less than one-tenth of Pinterest's current valuation. The stock trades for about 65% less than its SPAC valuation.

Nextdoor certainly has a long way to go when it comes to monetization and profitability. Its average revenue per user is a small fraction of what other major social media platforms generate from U.S. users, and the company just posted a negative 68% net margin in the second quarter.

Having said that, Nextdoor could be a home run if it can figure out the monetization question. Unlike most other social media platforms, Nextdoor's user base is growing fast. There are nearly 37 million weekly active users, an increase of 26% from a year ago, and the platform is proving its value to advertisers with lower costs per visit than competitors. If the company can keep growing and scale to profitability, it could be a massive winner for patient investors.

Know what you're getting into

To be perfectly clear, neither of these are low-risk stocks by any definition of the term and should be approached accordingly. There's plenty that needs to go right for these companies to be successful long term, and there's a lot that can go wrong in the meantime.

Having said that, both of them clearly have large market opportunities and if they can figure out how to profitably scale their businesses, the returns could be massive for patient investors.