Hertz shares soared as much as 17% on Wednesday after the company said it would sell its used cars on Amazon’s automotive marketplace. For the day, they rose 6% to close at $5.5

Hertz will list its used car inventory on Amazon Autos, starting with four cities before expanding to all 45 of the company's sales locations.

The partnership launched this week in Houston, Dallas, Los Angeles and Seattle, with plans to expand nationwide. It lets customers browse Hertz Car Sales’ inventory with Amazon’s shopping capabilities. Customers who buy online can pick up their vehicles within three days at a local Hertz Car Sales location.