Bitcoin bulls may want to pay closer attention to the miners.

In the last 24 hours, the companies whose computers perform the calculations that validate each transaction and are rewarded with new digital tokens, sold more coins than they mined, according to data from Cryptocomposite.com, a soon-to-be-launched analytics provider. Miners sold $17.3 million of coins, while they earned around $14.4 million, the company said.

While miners often sell newly minted coins to meet operating expenses such as electricity to run their networks, some observes say the extent of the sales could mean that the miners don’t anticipate Bitcoin will keep appreciating. Bitcoin has rallied 40 percent since the start of the month, pushing through $8,000 Tuesday for the first time since May.

“Historically, many miners didn’t sell 100 percent of their coins, and were waiting for the price to appreciate,” Kyle Samani, managing partner at Multicoin Capital Management, said in an email. “I suspect many of them are selling now.”

In prior recent days, miners have sold about $10 million worth of inventory, which is less than what they earned daily, according to Charlie Morris, who is on the team developing Cryptocomposite.com. He manages $300 million in assets for London-based Newscape Capital Group.

Despite the recent rally, miners have seen margins shrink since prices peaked at almost $20,000 in December. As prices lingered below $8,000, many miners’ margins were squeezed to the point that they were selling all their newly earned coins to cover expenses, and some miners left the market, according to analytics provider Coinmetrics.

“I’d expect that at these relatively low price levels, miners are selling off all of their new takings — they can’t afford not to,” Nic Carter, co-founder of Coinmetrics, said in an email.