Facebook Inc's (FB - Get Report) already slim chances of being the first company to a trillion-dollar market cap just got a lot slimmer.

The social networking giant's roughly 20% plunge on Thursday following a disastrous second-quarter earnings report wiped out more than $100 billion from Facebook's market cap, dropping its valuation to just over $500 billion and putting it in danger of being passed by Alibaba (BABA - Get Report)  ($503 billion) and Warren Buffett's Berkshire-Hathaway BRK.B ($494 billion) as the world's fifth-most valuable public company.

Meanwhile, Apple Inc. (AAPL - Get Report) continued to inch closer to the finish line, while Alphabet Inc. (GOOGL - Get Report) and Microsoft (MSFT - Get Report) , which both reported strong second-quarter earnings recently, gained slightly on Amazon.com Inc.  (AMZN - Get Report) , which reports its own Q2 earnings on Thursday after the close (TheStreet will be live blogging Amazon's second-quarter earnings and analyst call; please check our home page then for more details).

It's turning into a horse race, for sure.

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