Uber offers service for putting business travel on companies' tab

Ridesharing app Uber is now offering a plan called Uber for Business, in which employees can use Uber and bill their companies for business travel. Employers can create an Uber account for their employees to use and be able to have access to an employee's travel information.

Ridesharing app Uber is tapping into the massive business car service market, announcing on Tuesday a plan that allows users to bill their companies directly for the service.

With Uber for Business, employers can create an account with the car service, and then subsequently invite employees to join. Managers will then have easy access to an employee's travel information.

The company also announced partnerships with American Express and spend management company Concur Solutions. American Express cardholders will earn double points on Uber rides, while companies that already use Concur to handle travel and expense payments will be able to link their accounts with Uber.

For Uber, this is another big growth opportunity. They company already is valued at $18 billion, about the size of Hertz and Avis combined.

Uber's smartphone app allows users to order cars within minutes driven by both professional and nonprofessional drivers, and is now available in more than 130 cities. Uber CEO Travis Kalanick has said in interviews that revenue is doubling every six months, and that the company is growing faster this year than last year.

But all that growth has come at a cost: Uber is facing resistance from state regulators who want Uber drivers to adhere to the same rules and regulations for traditional taxi and limo drivers. And Uber is also facing competition from similar rideshare services such as Lyft.