Disclosure: The author of this story owns shares of the following bitcoin miners: IREN (IREN), MARA Holdings (MARA), Cipher Mining (CIFR), Bitfarms (BITF), Riot Platforms (RIOT) and CleanSpark (CLSK).

Bitcoin (BTC) miners are facing the strangest sort of existential threat in this era of scant profits: They can pivot to powering artificial intelligence (AI) or high-performance computing (HPC) and watch their stocks soar, or they can stick around and dominate their original turf, but see a languishing stock price.

That was the tale of mining in September, anyway, in terms of equity returns.

Miners with the largest market capitalizations – MARA Holdings (MARA), Riot Platforms (RIOT) and CleanSpark (CLSK) – all increased their share of the total amount of bitcoin mined last month versus August. These companies have much stronger balance sheets and larger mining operations, which is helping them navigate the reduction in mining profitability spurred by the bitcoin halving in April.

However, investors aren’t paying a premium for their stocks, as they continued to underperform in September. Meanwhile, miners putting focus on AI and HPC computing, such as Core Scientific (CORZ), TerraWulf (WULF) and IREN (IREN), beat bitcoin in September.

The shift in investor sentiment isn’t surprising, as the halving in April – which cut by 50% the reward for mining BTC – has made mining more competitive with narrower profit margins. Adding to the negative sentiment, the recent approval of spot bitcoin exchange-traded funds (ETFs) in the U.S. has reduced investors’ appetite for mining stocks.

Instead, investors are rewarding miners that now use part of their data centers to host AI- and HPC-related machines to diversify their revenue. AI and HPC computing require a large amount of power, which bitcoin miners have already secured, making them an attractive resource for AI and HPC companies that want to quickly ramp up their businesses.

In fact, looking at the share prices of publicly traded miners in September, stocks of miners with larger market caps rose between 4% and 9%. Miners with links to AI and HPC saw gains as large as 25% for the month. Bitcoin’s price rose about 7%, while the CoinDesk 20, a broad crypto market benchmark, climbed about 12%.

Miners are already surging in October, too, despite bitcoin trading relatively flat. Riot is up 12% and Cipher Mining (CIFR) is up 8%. October is also historically one of the strongest months for bitcoin, earning it the nickname “Uptober.”

Mining economics are tough after the halving.

The hashrate of the Bitcoin network, on a seven-day moving average, rose to an all-time high of 693 exahashes per second, or EH/s, while maintaining an average hash rate of 630 EH/s. Hashrate, a proxy for how competitive mining is, measures how much computing power is online on the network.

September also saw bitcoin difficulty – a measure of how hard it is to mine a new block in the network – hit an all-time high. Bitcoin’s difficulty is a measure of how hard it is to mine a new block in the network, which adjusts every 2,016 blocks based on the computational power, ensuring the blocks are consistently mined every 10 minutes. Meanwhile, the hashprice, a measure of miners’ profitability, hit a one-month high at $48.0 PH/s, according to Glassnode, despite remaining near all-time lows.

Drilling down into the individual miners’ monthly data, it seems MARA – the largest publicly traded miner with a market cap of $4.8 billion, and the company formerly known as Marathon Digital – had a successful September, increasing their energized hash rate by 5% in September to 36.9 EH/s. MARA also mined 705 BTC, a 5% increase from the previous month and the most mined in a single month since the halving in April. The firm also increased its BTC holdings to 26,842, the second-largest bitcoin stockpile among publicly traded companies, trailing only MicroStrategy. At the same time, it remained on track to reach 50 EH/s by the end of 2024.

The third-largest miner by market cap, Riot Platforms, also increased its mined bitcoin by 28% during September, as the company increased computing power across its facilities. Riot estimates to hit a hashrate of 36.3 EH/s in the fourth quarter of 2024 and 56.6 EH/s by the second half of 2025. Riot currently holds 10,427 BTC in its balance sheet.