Complex sentence: In November 2010, based on SecondMarket Inc. (an exchange for privately held companies'shares), Facebook's value was $41 billion; it slightly surpassed eBay's to become the third largest American web company after Google and Amazon.com.
Split into simpler sentences: In November 2010, based on SecondMarket Inc. (an exchange for privately held companies'shares), Facebook's value was $41 billion. The company had slightly surpassed eBay to become the third largest American web company after Google and Amazon.com.