Activist investor Carl Icahn is opposing a Dell Technologies Inc. stock-swap plan that he says undervalues shares in a tracking stock for Dell majority-owned VMware Inc.

In an open letter sent to stockholders of Dell's DVMT tracking stock, Icahn said that entities that he controls have acquired over 16.5 million, or 8.3%, of DVMT shares over the past few months, and the Icahn entities will vote against Dell's plan for the stock. Icahn also said he is considering putting forth a partial bid for the shares in an attempt to balance the competing interests of shareholders that want to sell and those that do not.

Dell went private in 2013 when Silver Lake Partners agreed to acquire the company for $24.9 billion. The DVMT stock was created to help fund Dell's acquisition of EMC Corp., which is now Dell EMC.

If Dell chooses to go through a traditional IPO route instead, the offering could be the largest go-public transaction in the systems software sector in over a decade, considering the value of VMware alone in its 2007 offer. Dell confirmed earlier this month that it is considering an IPO if its stock-swap plan fails. Icahn, however, said he believes that a Dell IPO would underperform the company's expectations. Technology stocks have seen trading volatility this year.