Uber Challenge Is a Test for ‘Sharing’ Economy

The most serious challenge to Uber Technologies Inc.’s “Be your own Boss” business model might also present an early test to the wider “sharing” economy as well as undermine its own $50 billion valuation.

The immediate battle comes Thursday in San Francisco, where Uber is seen as having a difficult task in persuading U.S. District Judge Edward M. Chen to block a lawsuit seeking to reimburse 160,000 California drivers for mileage and tips from proceeding as a class action.

Chen’s decision hinges on the broader issue of whether Uber drivers are independent contractors, as the company claims, or employees entitled to ...