The financial impact of software defects

According to a study commissioned by the National Institute of Standards and Technology, in 2002 software errors were estimated to cost 0.6% of gross domestic product in the U.S. In real money, that's $59.6 billion per year lost or spent because of errors. The study also suggests that more than a third of these costs could have been avoided if testing had been properly in place, particularly early in the product development lifecycle (National Institute of Standards and Technology 2002).

Source: Training material - Software Testing module (IBM Certified Specialist - Software Quality certification)