The upgrade stems from Huntsman's improving free cash flow and the possibility for a higher valuation multiple following its Venator spin off by the end of Q2, Citi analyst P.J. Juvekar wrote.
Juvekar also illustrated management's willingness to enhance shareholder value through a potential merger of equals.
Shares of Huntsman closed lower Monday by .86% to $24.32 on heavy trading volume.
This story has been updated from 11:12 a.m. EDT.