How Sarao 'spoofed, layered' his way to $1-mln flash crash gain

SAN FRANCISCO, April 21 (Reuters) - To generate $40 million in gains over a period of four years, including nearly $1 million in the May 2010 U.S. stocks "flash crash," Navinder Singh Sarao used a couple of fairly simple techniques that let him push futures prices down, buy the contracts on the cheap, and then profit from the sale.