Yield management spread to other travel and transportation companies in the early 1990s. Notable was implementation of yield management at National Car Rental. In 1993, General Motors was forced to take a $744 million charge against earnings related to its ownership of National Car Rental. In response, National's program expanded the definition of yield management to include capacity management, pricing and reservations control. As a result of this program, General Motors was able to sell National Car Rental for an estimated $1.2 billion. Yield management gave way to the more general practice of revenue management. Whereas revenue management involves predicting consumer behavior by segmenting markets, forecasting demand, and optimizing prices for several different types of products, yield management refers specifically to maximizing revenue through inventory control. Some notable revenue management implementations include the NBC which credits its system with $200 million in improved ad sales from 1996 to 2000, the target pricing initiative at UPS, and revenue management at Texas Children's Hospital. Since 2000, much of the dynamic pricing, promotions management and dynamic packaging that underlie e commerce sites leverage revenue management techniques. In 2002 GMAC launched an early implementation of web based revenue management in the financial services industry.