Back in 2021, there was a whole wave of investors looking to get crypto exposure without actually holding digital assets themselves. Remember that? The play was to buy cryptocurrency stocks instead - companies that were basically riding the blockchain wave. I remember seeing this shift happen pretty clearly around that time.

There were a few names everyone was watching. First up was Coinbase, which had just gone public. The platform was massive - over 43 million users across 100+ countries. Their Q2 numbers were insane that year: $2.33 billion in revenue, way above what analysts expected. They were pulling in $1.9 billion from transaction fees alone, plus another $100 million from subscriptions. Their transacting users jumped 44% quarter-over-quarter to 8.8 million. The company was clearly on a growth trajectory as cryptocurrency stocks to buy in 2021 became increasingly attractive to mainstream investors.

Then there was Riot Blockchain, which was basically all-in on Bitcoin mining. They announced in August that their mining revenue hit a record $31.5 million - that's a 1540% year-over-year jump. Wild numbers. They went from a $10.6 million loss the previous year to $19.3 million in net income. By September, they were producing 406 BTC monthly and holding around 3,534 total. Their whole strategy was becoming one of the lowest-cost Bitcoin producers in North America.

Hut 8 Mining was another interesting play. This Canadian company was mining Bitcoin and building infrastructure. HUT stock had already run up over 1200% in the year leading up to that point. They got certified as an authorized repair center for MicroBT miners across North America, which gave them better access to equipment and resources. By September 2021, they'd mined 264 Bitcoin that month alone and were sitting on 4,724 self-mined Bitcoin - ahead of their original targets.

PayPal was the last one worth watching. They were integrating crypto into their ecosystem in a big way that year. Launched a new all-in-one app where users could manage payments, shopping, savings, and cryptocurrency all in one place. Research suggested digital wallet usage would double to 4.4 billion people globally by 2025, so PayPal was positioning itself right in the middle of that trend.

Looking back, cryptocurrency stocks to buy in 2021 represented this interesting middle ground - you got exposure to the crypto boom without the volatility of holding actual coins. Whether it was fintech giants like PayPal and Square accepting crypto, or pure-play mining companies, or platforms like Coinbase, there were definitely options for different risk appetites. The space was moving fast back then.