(Reuters) -Two Seas Capital, the largest shareholder of Core Scientific ( CORZ ), issued an open letter on Thursday saying it would vote against the company's proposed sale to CoreWeave ( CRWV ), in a potential blow to the $9 billion deal.

The investment management firm owns roughly 6.3% of the crypto miner and said the sale "materially undervalues" Core Scientific ( CORZ ) and unnecessarily exposes its shareholders to substantial economic risk.

"We do not believe this transaction should receive shareholder approval," it said.

CoreWeave ( CRWV ) announced its intention to buy Core Scientific ( CORZ ) last month in an all-stock deal, as it seeks to tap into more data center capacity in order to meet growing demand for artificial intelligence services.

CoreWeave ( CRWV ) provides access to data centers and Nvidia-powered AI chips to companies seeking to train large language models.

Two Seas says the transaction "decidedly and unfairly favors CoreWeave ( CRWV ) at the expense of Core Scientific ( CORZ ) shareholders."

At the time of announcement, the deal valued Core Scientific ( CORZ ) at $20.40 per share.

The firm says it is not "philosophically" opposed to a merger but emphasizes that the board's job is to ensure that any deal should reflect strategic value of Core Scientific's ( CORZ ) assets.

Shares of Core Scientific ( CORZ ) were marginally up, while CoreWeave's ( CRWV ) stock was 6% higher but unchanged on the news.

The crypto mining firm's stock ended over 17% lower on the day the merger was announced.

Core Scientific ( CORZ ) did not immediately respond to a Reuters request for comment; CoreWeave ( CRWV ) declined to comment.

Bitcoin miners' energy-intensive sites and power contracts, built during the crypto boom, have emerged as prime targets for AI companies expanding their computing infrastructure.

Core Scientific ( CORZ ) came out of bankruptcy in early 2024 and has since shifted its focus to leveraging its energy capacity to lean on AI.

Core Scientific ( CORZ ) first received an unsolicited, non-binding takeover offer from CoreWeave ( CRWV ) in June 2024. At the time, the company rejected the offer, saying it was significantly undervalued.