A number of companies are investing in autonomous driving technology including Apple and Alphabet. Amazon has been surprisingly absent from the discussion, but that’s changing as the online retailer has invested in Aurora.

In a Medium post, Aurora confirmed its latest round of funding was able to secure $530 (£409 / €467) million thanks to investments from Amazon, Sequoia and “accounts advised by T. Rowe Price Associates.” Aurora went on to specifically highlight the Amazon investment as they noted the retailer’s “unique expertise, capabilities and perspectives will be valuable for us as we drive towards our mission.”

Aurora also noted its latest round of funding will help them accelerate the development of their autonomous driving technology and strengthen their team as well as their ecosystem.

While Aurora doesn’t have the name recognition of Waymo or Cruise Automation, the firm was founded by Chris Urmson, Sterling Anderson and Drew Bagnell. The trio has years of experience in the field as Urmson was the Chief Technology Officer for autonomous vehicles at Google’s Alphabet and Anderson led the team that created Tesla’s Autopilot.

Aurora has kept a relatively low profile, but the company is partnering with Hyundai to develop Level 4 autonomous vehicles which are slated to arrive by 2021. The partnership will initially focus on custom-developed vehicles, but the two companies will work to “commercialize self-driving vehicles worldwide” in the long term.

We have heard much about the partnership since it was announced in January of last year, but Level 4 vehicles can drive themselves without human involvement certain conditions. At the time, the two companies said the goal of the partnership was to deploy these vehicles quickly, broadly and safely.