With corporate travel surging due to a red-hot economy, business travelers are increasingly turning to ride-hailing firms when they are on the road.

Year-end analysis of more than 50 million expense reports in 2017 by the expense management firm Certify, shows Uber and Lyft were the choice for more than two-thirds of the corporate travel receipts it analyzed.

Overall, 68 percent of the ground transportation receipts Certify looked at in 2017 were for trips taken with Uber or Lyft. By comparison, just 56 percent of the receipts for ground transportation in 2016 came from ride-hailing firms.



Meanwhile, Certify said business travelers are renting fewer cars and taking taxis less often while on the road. Overall, rental car receipts fell 8 percent to make up 25 percent of ground transportation receipts analyzed by Certify. Taxi receipts fell 4 percent, and accounted for 7 percent of the category.



The shift to Uber and Lyft over the last three years by business travelers is one reason investors have soured on rental car stocks. Shares of Hertz have dropped 71 percent over the last three years while Avis Budget Group is down 19 percent over the same time period. By comparison, the S&P 500 has climbed 41 percent over the last three years.



Whatever mode of transportation business travelers use, it's clear corporate travel is not slowing down, Certify said.



"A healthy business travel market is a key driver of a strong economy, and year over year we are seeing a sharp increase in our business travel data," said Robert Neveu, CEO of Certify.

