Authors W. Chan Kim and Renée Mauborgne use the metaphor of the "blue ocean" to describe for companies their vision of expanding, competitor-free (or light) markets that reprsent "untapped market space" and the opportunity for "highly profitable growth". They claim that the reason more companies haven't "set sail" in search of these is that the majority of strategy work done over the past 25 years has been focused instead on "red oceans", where the emphasis is on how to take share away from market competitors. As examples of companies who have successfully gone into "blue oceans" the authors, both professors at France's INSEAD, the world's second largest business school, cite Southwest Airlines, Curves, Starbucks and Cirque du Soleil. They urge companies to "value innovation" that focuses on "utility, price, and cost positions," to "create and capture new demand".