Since October, shares of five cryptocurrency-mining stocks have spiked to 12-month highs of up to nearly five times their prices at this time last year. All five currently have market caps of more than $1 billion, and most have dropped between 40% and 50% of their share prices since November 10, when Bitcoin posted a 12-month high of more than $68,000.

Bitcoin has added more than 60% to its value over the past 12 months, but at a current price of around $47,500, the cryptocurrency trades about 30% lower than it did on November 10. And the bitcoin miners are taking a serious hit. Yet, they continue to add mining machines in pursuit of a payoff for being first to verify a block and add it to the blockchain.

Here are some data points that miners know and that investors should too:

• Only 21 million bitcoins will ever be produced.
• More than 18.9 million already have been mined (just over 90%).
• The reward to miners for verifying a block is currently 6.25 bitcoins (around $299,000 at the current price).
• The reward will be cut by 50% (known as block halving) sometime in 2024.
• The supply of bitcoins to mine is expected to be exhausted by 2040.

As the number of available bitcoins and the reward size fall, completing a block (which takes about 10 minutes) and earning the reward will continue to pay off because each bitcoin will be worth more. How much more? Ark Invest’s Cathie Wood, for example, has said that bitcoin prices could rise by another $500,000 as institutions increase their allocations to the digital currency to 5% of their portfolio’s value. Crypto miners with the highest hashrates (quintillion guesses per second) will have an advantage in capturing that wealth.

With that bit of background, let’s take a look at the five bitcoin miners with market caps of more than $1 billion. In the following comments, cash burn refers to negative free cash flow.

Marathon Digital

Marathon Digital Holdings Inc. (NASDAQ: MARA) has a market cap of around $3.48 billion, and the stock has added about 175% to its value over the past 12 months. The company recently announced that it will pay $879 million to acquire 78,000 mining machines from Bitmain in six deliveries of 13,000 machines in each of the past six months of next year. By the time all the miners are operating, Marathon will be generating some 23.3 exahashes per second in the company’s bitcoin-mining operations.