RE:PTA currently trades 1 times its 2015 EBITDA...You say:
" Based on Brent at $75/bbl for the entire 2015, PTA will make 2015 EBITDA at US$100 million, so it currently trades just 1 times its 2015 EBITDA. "
Your assumption means that WTI will be between $65 and $70, which is an overly realistic scenario. However, I believe that Brent will average between $80 and $90 in 2015.