The firm said in a letter to investors Wednesday that Shell would benefit from breaking off its liquefied natural gas, renewables and marketing businesses into a standalone company. That would separate it from Shell's legacy energy business, which would include the upstream, refining and chemicals operations. The effort to break up the 188-year-old Anglo-Dutch oil major, which has a market capitalization of about $190 billion, comes less than a year after activist investor Engine No. 1 ran a successful proxy contest to elect new directors to the board of Exxon Mobil Corp., in part over what it says is the company's lack of action on climate change.