Activist investor Dan Loeb said Tuesday that Dow Chemical Company (NYSE:DOW), which is now the largest holding in Loeb's Third Point LLC investment vehicle, needs to spin off its upstream and downstream petrochemical operations.

Loeb, according to Zero Hedge, wants the giant U.S. chemical company to back off from its vertical integration business model, according to a letter Loeb released Tuesday.

"Dow shares have woefully underperformed over the last decade, generating a return of 46 percent compared to a 199 percent return for the S&P 500 Chemicals," the letter said. "In April 1999 an investor could have purchased Dow shares for the same price that they trade at today!"

Such a step would let Dow become an industry leader in agricultural sciences and electronics and functional materials, Loeb's letter said.