Investor Carl Icahn said he will vote against Dell Technologies’ plan to acquire VMware tracking stock — a move that could sink the $9 billion deal.

Icahn also disclosed he holds 8.3 percent of DVMT, the stock that tracks Dell’s controlling stake in VMware. This makes him the second-largest shareholder.

The deal, under which tracking stock shareholders would receive $109 per share, undervalues DMVT stock, Icahn said. In an open letter to shareholders, he wrote that “on a pure mathematical basis” the tracking stock is worth about $144 per share. It currently sells for about $92 per share.

Icahn accuses Michael Dell of “scare tactics,” and blames poor corporate governance as well as Dell’s 2013 effort that took his company private for this “massive distortion.” “The market does not trust Michael Dell or Silver Lake,” he wrote. Icahn also fought against Dell going private in 2013.

Dell Technologies did not immediately respond to a request for comment.

The activist investor urges stockholders to vote against the tracking stock proposal. “I intend to do everything in my power to STOP this proposed DVMT merger,” he wrote.

Other shareholders including Elliott Management, some teams at BlackRock, Dodge & Cox, Farallon Capital Management, and Canyon Capital Advisors are also planning to reject the deal, according to an earlier Wall Street Journal report.

On Again, Off Again IPO

After mulling a merger, Dell and VMware in July reached a $9 billion deal under which Dell would acquire DVMT. It issued the tracking stock to fund its EMC acquisition in 2016. Buying DVMT would allow Dell to be publicly listed on the New York Stock Exchange without a formal initial public offering.

Shareholder opposition to the acquisition, however, prompted Dell to put an IPO back on the table. And in an Oct. 3 filing with the U.S. Securities and Exchange Commission, Dell confirmed that an IPO is its backup plan and said it has met with investment banks to discuss this option.

Icahn calls this “an empty and ridiculous IPO threat” and says the company would face “significant challenges” in going public.