Waymo, the self-driving unit of Alphabet Inc, said on Monday it has raised $2.25 billion in its first external investment round.

The first external investment round is led by Silver Lake, Canada Pension Plan Investment Board, and Mubadala Investment Company. Additional investors in this initial $2.25 billion close include Magna International, Andreessen Horowitz, and AutoNation, as well as Alphabet.

Last September, investment bank Morgan Stanley slashed its projected valuation of Waymo to $105 million from its earlier estimate of $175 million, saying the commercialization of self-driving vehicles and technology was taking longer than expected.

This investment round follows a recent series of major operational and technical milestones. The Waymo Driver has driven more than 20 million miles on public roads across over 25 cities, and over 10 billion miles in simulation. Engineers and technicians at Waymo's Detroit factory, the world’s first factory dedicated to the mass production of L4 autonomous vehicles, have shipped the first vehicles (electric cars and Class 8 trucks) integrated with fifth-generation hardware, with all-new, more powerful compute and more capable sensing.

Waymo One, the world’s first public self-driving ride-hailing service, serves thousands of customers in Arizona and has already provided thousands of fully driverless rides to Waymo's riders, in a high-speed mixed usage market area larger than San Francisco. The Waymo Driver is now deployed across a variety of vehicle platforms and business applications, including Waymo Via, which is focused on all forms of goods delivery.