Uber wants to be the world’s private driving service. Now the company is amassing the war chest to do it.

The startup closed a new $1.2 billion round of financing Thursday, with investors valuing the company at $40 billion.

The latest haul piles a new mountain of cash on top of the $1.5 billion that Uber had already raised. And it may collect more: Uber may eventually sell an additional $600 million in stock, and it is working with Goldman Sachs to sell, potentially, another $1 billion in debt to some of the Wall Street firm’s wealthy private clients.

Uber’s ascent is one of the most rapid by a startup in years. Five years ago, Uber was just an app that allowed customers to summon a private car with the push of a smartphone button. Since then, it has surged in growth to surpass even other members of Silicon Valley’s exclusive 11-digit club — startups whose valuations exceed $10 billion.

With the additional money, Uber is setting itself up for what its investors hope will be the next mammoth initial public offering.

The new money, however, comes amid a rash of fierce criticism about the company’s approach to users’ privacy. While people briefed on the fundraising process said that the recent controversy did little to diminish enthusiasm among investors, Uber acknowledged Thursday that it had more growing up to do.

Raising more cash is another step in Uber’s plan to become to become the world’s premier logistics service, capable of transporting people to places they want to go as quickly and seamlessly as possible.

The company has also signaled its ambitions to be a one-stop shop for delivering anything, anytime, anywhere.

“Millions of people may decide that they no longer need to own a car because using Uber will be cheaper than owning one,” Travis Kalanick, Uber’s chief executive, wrote in a blog post Thursday announcing the new round of funding.

Accomplishing that goal will require huge amounts of capital and chutzpah. In every new market, the company must wage battles with the existing taxi and limousine industries, curry favor with local regulators and persuade local drivers to switch en masse to Uber’s service.

“There’s an entire thriving transportation ecosystem that’s being disrupted here,” said Susan Shaheen, a professor at the University of California, Berkeley, who studies civil engineering and transportation companies. “Startups like Uber are up against the taxi companies, the charter party carriers, not to mention the shuttle industry. We’re in early days here.”