Mark Spitznagel (born March 5, 1971) is an American investor, derivatives trader, author, and sustainable farmer. Spitznagel is known for his über-bearish “Austrian”-based stock market investing and pioneering “tail-hedging,” and most notoriously for his hugely profitable billion dollar derivatives bet on the stock market crash of 2008, as well as for having allegedly caused the stock market crash of 2010.