When David Shaw turned 50 in 2001, he paused to take stock of his life. D.E. Shaw & Co., the New Yorkbased investment firm he had founded more than a decade earlier, was thriving. Its core business -- a quantitative-based hedge fund that relies on sophisticated computer-driven algorithmic models to find mispriced securities -- had grown from $28 million in 1988 to more than $3 billion.
