Hertz Will Sell Cars on Amazon. Carvana Stock Slides.

Hertz is Amazon’s first fleet customer, according to the rental car company. (Cindy Ord/Getty Images)

Hertz Global Holdings stock jumped Wednesday after the car-rental company announced it plans to sell cars on Amazon .com.

Hertz shares added 6%, closing at $5.51, while the S&P 500 fell 0.2% and the Dow Jones Industrial Average rose less than 0.1%. Amazon stock fell 1.8% to $223.81. Wednesday’s gain left Hertz stock up 41% year to date.

“Our goal is to reimagine the car-buying experience and meet customers where they are, whether online or in person, with convenience, confidence, and scale,” said Jeff Adams, executive vice president of Hertz Car Sales, in a statement.

“Amazon Autos is the ideal partner to help us deliver on this, as customers can shop our expansive inventory of high-quality used cars on the same trusted marketplace where millions shop every day.”

Cars are already for sale on Amazon: “Amazon Autos” partners with dealers. It appears similar to search tools on Autotrader.com or Cars.com.

Hertz, however, is Amazon’s first fleet customer, according to Hertz’s news release. Amazon Autos expanded its service into certified pre-owned vehicles in August, according to the company.

As for Hertz’s stock move, investors seem to think the company will get better margins on the company’s vehicles sold on Amazon. That may be the case, but online distribution platforms for used cars aren’t new or underdeveloped. Car rental companies routinely buy and sell vehicles.

The Hertz move could hit shares of car dealers or online platforms such as Cars.com. Amazon Auto represents competition for listings and used-car inventory. Carvana stock dropped 1.7% to $338.61. CarGurus stock slipped 2.2% to $31.74. Cars.com stock was off 1.6% at $12.05.

“Bottom line, we view the news as a negative for both Carvana and CarGurus, but note that Amazon’s expansion into used vehicle sales has been expected for some time,” wrote Gordon Haskett analyst Robert Mollins on Wednesday, noting that Hertz and Carvana have been partners since 2021.

“Amazon expanding to used vehicles poses a risk to CarGurus’ listing marketplace and Digital Deal product,” added Mollins. “But [we] acknowledge that headwinds will take time to mount as Amazon will need to attract a large number of dealers in order to effectively compete against CarGurus and other listing sites.”

Amazon has the power to disrupt industries—and investors’ thinking. This past week, shares of Kroger dropped almost 6% in the two days after Amazon’s plan to expand same-day delivery of groceries.

Write to Al Root at allen.root@dowjones.com