Mr. Kalanick, Uber’s outspoken chief executive, has courted controversy with questionable comments and ruthless competitive tactics.

Uber

As of January 2016:

Latest valuation: $51.0b (August 2015)

Total equity funding: $7.4b

Valuation-to-funding: 6.9 to 1

Rounds of funding (current): 8

Location: San Francisco, Calif.

Founded in 2009

CEO: Travis Kalanick (co-founder)

CEO Travis Kalanick  Photo: Agence France-Presse/Getty Images

Competitors: Lyft, Sidecar, Hailo, Didi Dache, Kuaidi Dache, Ola Cabs

Investors: Baidu, Benchmark Capital, Bezos Expeditions, Blackrock, Fidelity Investments, First Round Capital, Founder Collective, Goldman Sachs, Google Ventures, Jumpstart Capital, Kleiner Perkins Caufield & Byers, Lone Point Capital, Lowercase Capital, Menlo Ventures, New Enterprise Associates, Qatar Investment Authority, Summit Partners, TPG Growth, Valiant Capital Management, Wellington Management

A pair of serial entrepreneurs, Travis Kalanick and Garrett Camp, struck gold in 2009, when they developed a smartphone app that could summon a private taxi with the press of a button.

Uber launched in their home city of San Francisco the following year, shuttling affluent young professionals around the booming tech metropolis in black Lincoln Town Cars with white-glove service. Passengers loved the convenience; drivers found an extra source of income and Uber built a business by pocketing 20% of each ride.

With its model proven, Uber plotted a rapid global expansion, bringing the service to more than 270 cities around the world in five years. The company’s success has sprouted imitators like Lyft and Sidecar as well as opposition from the incumbent taxi industry and regulators who have raised concerns about safety. The service has been banned in Nevada and and outside the U.S. in parts of India, China and Thailand.

Mr. Kalanick, Uber’s outspoken chief executive, has courted controversy with questionable comments and ruthless competitive tactics. Investors, however, have grown ever more enamored with the company, sending its valuation to $50 billion in July, equaling Facebook Inc.'s record for a private, venture-backed startup.

Mr. Kalanick has proven to be an adept fundraiser, even creating strange bedfellows among corporate rivals such as Microsoft Corp., Google Inc. and Amazon.com Inc. founder Jeff Bezos.

With a war chest of billions, a vast network of lawyers and lobbyists and veteran political operative David Plouffe, Uber is working to ease passage of laws that will bring its service into compliance with municipal codes. Uber is investing billions of dollars in China and India to battle regulatory roadblocks and local competitors.

Mr. Kalanick has also hinted at a more ambitious next act for the company: transforming from a transportation provider for people into a logistics provider moving all manner of goods and services from point A to point B.