(Bloomberg) -- Pierre Andurand, one of the most bullish oil investors, recorded the best monthly gain in his hedge fund in almost four years and erased 2018 losses as crude prices surged in September. The $1.2 billion Andurand Commodities Master Fund gained 14.7 percent last month, the most since December 2014, according to a letter to investors seen by Bloomberg. That boosted the return for this year to 11.3 percent. A spokesman for the London-based money manager declined to comment. Andurand benefited from a surge in energy prices in late September that took oil to above $80 a barrel.