In September, Riot Platforms (RIOT -4.85%) stock dropped down to almost $6 per share, falling to its lowest price in nearly two years. In the three short months since, Riot Platforms stock has more than doubled. And some investors believe it's just getting started.

Investors believe Riot Platforms stock could be in for more gains because of what's happened with MicroStrategy (MSTR -3.24%) stock in recent years. For context, MicroStrategy stock went public in 1998 and it had gone nowhere as of the end of 2019. But MicroStrategy stock is suddenly up more than 2,500%, just since the start of 2020.

The difference for MicroStrategy stock has been its policy regarding cryptocurrency Bitcoin (BTC 0.74%). Over the last few years, the company has gone to great lengths to get its hands on as much cash as possible. And as of Dec. 16, it had managed to spend over $27 billion on buying Bitcoin.

MicroStrategy executive chairman and co-founder Michael Saylor has obviously overseen an outsized portion of its policy changes regarding Bitcoin. And that's why investors have been paying attention to the praise he's heaping on Riot Platforms.

Can Riot Platforms work the same playbook?

Saylor keeps using his social media presence to point out that Riot Platforms is "on the Bitcoin standard." By this, he's highlighting the recent change to the company's approach to Bitcoin.

Riot Platforms is a Bitcoin mining company, which means that it regularly receives Bitcoin just for doing business. At the end of November, the company had 11,425 Bitcoins, and it had mined all of them. But management wants more than this. And it's not waiting around to get them through mining.

On Dec. 9, Riot Platforms decided to raise money by issuing convertible notes. But rather than use the money for business purposes, management said it planned to primarily use it to buy Bitcoin.

Riot Platforms wound up netting $579 million from the debt offering, which is massive considering its market capitalization was about $4 billion at the time. And management has already been busily buying Bitcoin with its newfound fortune. As of Dec. 13, it had 17,429 Bitcoins, worth about $1.8 billion as of this writing.

In short, Riot Platforms added 6,000 Bitcoins in just two weeks.

Debt is one of the tools that MicroStrategy has used to increase its own Bitcoin holdings. As of Sept. 30, the company had nearly $4.3 billion in aggregate principal from its issued convertible notes, whereas it had been a debt-free company a few years ago.

To put it simply, MicroStrategy has used debt (and stock offerings) to purchase Bitcoin. But the price of Bitcoin is close to an all-time high and is up over 150% in just the past year. This has boosted MicroStrategy's valuation, making it easier to get additional funds.

The idea is that Riot Platforms can run a very similar playbook. It intends to keep mining Bitcoin, yes. But it also intends to keep finding ways to raise more cash and buy Bitcoin on the open market. If the price of Bitcoin keeps going up, it could be a rewarding venture for shareholders.

The upside opportunity for Riot stock

Generally speaking, I'm not a fan of businesses that load up on debt because it adds another layer of risk to the investment. I think that investors need to acknowledge this risk and others when thinking of buying Riot stock, or any stock for that matter.

However, to look at things more optimistically, Riot says that it has a year-to-date Bitcoin yield of 37%. This is a term being used by several companies, including MicroStrategy, that basically means the percentage increase for Bitcoin holdings per diluted share. For investors hoping to see Riot run the MicroStrategy playbook, this 37% yield is quite exciting.

For perspective, MicroStrategy has a great year-to-date Bitcoin yield of 72%. But this isn't an apples-to-apples comparison with Riot because MicroStrategy was working this strategy all year whereas Riot just started. Looking at more recent moves, Saylor says that MicroStrategy's Bitcoin yield was only 3% during the first week of December.

Without going too deep into the weeds, it seems that given the current valuations, Riot might be in a better position to hit a higher Bitcoin yield when compared to MicroStrategy, at least for now.

As long as the price of Bitcoin holds steady or keeps rising, that could make Riot Platforms stock the better stock to buy today. But to reiterate, both companies are running a risky strategy that depends on several factors outside of their control, including stability in the crypto space, stock market conditions, and institutional appetite for funding the debt.

In closing, Riot stock could be a winner with its current strategy but investors need to avoid overconfidence about the future here. And you don't have to choose MicroStrategy or Riot -- you can always skip the debt risk by investing in Bitcoin directly instead.