MicroStrategy (MSTR) shares plummeted more than 16% after short seller Citron Research said it had taken a new bet against the stock, which has gained over 500% this year.

Even with Thursday's decline, MicroStrategy stock has soared more than 50% since crypto-friendly President-elect Donald Trump’s victory earlier in November. Bitcoin itself is up roughly 30% over the same period, hitting a fresh record of $98,000 Thursday.

The software-company-turned-bitcoin-play disclosed earlier this week it purchased another 51,780 bitcoins for approximately $4.6 billion in cash at an average price of just over $88,500 per bitcoin. The company has acquired a total of 331,200 bitcoins for $16.5 billion, spending an average of 49,874 per bitcoin.

This stock surge, however, has caught the attention of investors who see this meteoric move in 2024 as potentially unsustainable.

In a post on X early Thursday, Citron Research said that while the firm remains bullish on bitcoin — and was bullish on MicroStrategy's bitcoin play years ago — the move in MicroStrategy stock has "completely detached from BTC fundamentals."

"Bitcoin is dramatically beating the 'Magnificent Seven,'" MicroStrategy chair Michael Saylor said in the company's most recent earnings call in October, adding, "Your best hope to actually keep up with the Magnificent Seven is constructive bitcoin strategy."

Read more: Bitcoin clears another record: Is this a good time to invest?

The company, in recent years, adopted bitcoin as its primary Treasury reserve asset through investments funded by equity, debt financing, and its own cash flows under the leadership of Michael Saylor, who served as CEO until 2022 before assuming the role of chairman.

MicroStrategy began investing in bitcoin in 2020 with what now seems like a measly $250 million investment.

"We pride ourselves on being at the forefront of institutional bitcoin adoption," CFO Andrew Kang said in the company's Oct. 30 earnings call.