Oct 27 (Reuters) - Activist investor Daniel Loeb"s Third Point has built a near $750 million stake in Royal Dutch Shell (RDSa.L), a source close to the matter told Reuters on Wednesday, and is arguing for a breakup of the oil major. In a letter to its own investors, seen by Reuters, Third Point said Shell had "too many competing stakeholders pushing it in too many different directions, resulting in an incoherent, conflicting set of strategies." Third Point said the creation of multiple standalone companies would make it easier for Shell to return cash to shareholders from "legacy" businesses such as upstream oil and gas, oil refining and chemicals. At the same time, a separate liquefied natural gas (LNG), renewables and marketing business could "combine modest cash returns with aggressive investment in renewables and other carbon reduction technologies", at a lower cost of capital.Third Point said it was in the early stage engagement with Shell but was confident Shell"s board and management can devise a plan to decarbonise faster and improve shareholder returns. The Wall Street Journal, which first reported the development, had put the size of the stake at more than $500 million, citing people familiar with the matter. Shell did not immediately reply to Reuters" requests for comment and for confirmation of the size of Third Point"s stake in percentage terms. Shell"s market capitalisation stood at just under $190 billion on Wednesday. Shell, which is due to publish third-quarter results on Thursday, is the world"s biggest fossil fuel retailer and aims to become one of the world"s biggest renewable electricity traders. Smaller Shell rivals Eni (ENI.MI) and Repsol (REP.MC) have already flagged plans to spin off parts of their renewables businesses to help finance their transition to offering more lower-carbon products. read more