A few months ago Goldman owned ~7% of the company shares. Did they dump those shares prior to their downgrade or did they just short the stock? There hasn't been any significant news to substantiate going from a major shareholder to a seller in the last two months. Obviously, Goldman is trying to manipulate the share price to it's own advantage. SEC where are you?
If one compares the highs and the lows of the two companies then it seems NGLS has the same potential for capital appreciation as TRGP while paying double the dividend. As far as TRGP being the "parent" what assets does it own outside of NGLS. How are those assets performing?