Here's the only way Uber can justify its $41 billion valuation

Ride-hailing behemoth Uber has been valued at $41 billion, making it one of the most valuable private tech companies in the world. A fresh round of funding could push that valuation even higher, giving the startup a dizzying $50 billion valuation. Uber is a five-year-old private company. It's still growing, fighting regulatory battles domestically and expanding internationally. But eventually, when it's ready to go public, Uber will have to prove its valuation somehow. And though the global tax...