A Tesla S electric car and a charging station are displayed during the press preview day of the North American International Auto Show in Detroit Thomson Reuters Tesla is selling more stock. The electric car maker said it plans to raise about $500 million through the sale of 2.1 million shares.

On Friday, it upped the offering, to about 2.7 million shares, raising $640 million.

CEO Elon Musk will himself likely buy 84,000 shares for about $20 million in the offering, according to a regulatory filing on Thursday.

This is a completely unsurprising move. It was anticipated by Wall Street but consistently downplayed by Musk and his management team.

Even as Tesla burns through substantial amounts of cash to launch a new vehicle, the Model X SUV, and construct a massive battery factory in Nevada, it has said that it would end the year with $1 billion in the bank and not need to tap its elevated stock price to raise additional capital.

However, on a conference call with analysts after Tesla reported second-quarter earnings, Musk admitted that if the company were planning an equity raise, now would be the time. Here's an exchange with Bank of America Merrill Lynch auto analyst John Murphy from the call (thanks to Seeking Alpha for the transcript).

"[W]hen you look at the cash burn and how the capital market sometimes shift very quickly, it just seems like an opportune time to take advantage of what you might need in the future, so that's why we're asking," Murphy said.

"[W]e're in the same sort of mind frame as you are," Musk responded.

At the time, Musk sounded as if he were grudgingly acknowledging Murphy's point. But it now looks as if he was telegraphing the equity raise, without getting into any specifics. And the bottom line is that is a genuinely ideal time for Tesla to sell equity, even if to a certain extent that's an admission that there isn't enough money coming in to mitigate the many risks that the company faces over the next few years.

In fact, Musk has repeatedly characterized equity raises as a strategic way to get ahead of risks to the electric-car startup.

A Model X prototype undergoing testing. YouTube/nbkagzw13

Tesla's ongoing challenge is that it's in a business that's highly capital intensive. It can cost a traditional car maker $1 billion to develop a new car, and the big automakers spend billions every quarter to construct and market vehicles. Tesla has to follow this script, but it's also constructing the multi-billion Gigafactory in Nevada, to supply enough battery cells to power a predicted 500,000 cars by 2020; and expanding it Supercharger network, effectively the gas stations that enable Tesla owners to travel longer distances without encountering "range anxiety."

Tesla can already tap a $750 million credit line that is established earlier this year. But in the last quarter, it spent $405 million, and given the company's ambitions, a lot of analysts and observers have been doing some back-of-the-envelope calculations and determined that a cash crunch was on the horizon.

A "gas" station for Teslas. Green Car Reports

Some new outlets erroneously reported that Tesla is losing $4,000 per vehicle at this juncture. This figure was arrived at by taking Tesla total quarterly loss and dividing it by the number of cars produced.

But that isn't why Tesla is losing money at the moment and needs to raise additional funding.

In response to an inquiry from Business Insider, a Tesla spokesman noted that the math behind a $4,000 loss per vehicle didn't take into account "one-time spends on Model X development or Gigafactory."

Investment in the Model X peaked in the second and third quarter, he added. This was the result of the typical upfront expenses to develop an all-new vehicles, ranging from design and engineering to crash testing.

Those costs should ease as the Model X rolls out in late September. But the cash burn will probably resume in 2016, as Tesla prepares to launch its next vehicle, the mass-market Model 3, scheduled to hit the streets in 2017.

For what it's worth, even as Tesla has pushed back against the equity-raise speculation for several quarters, it announced in June that CEO Deepak Ahuja would be retiring at the end of the year. Ahuja has generally been the the Tesla executive who has stressed that the company has enough money to stay in business. But news of the $500-million stock sale could prompt a fresh round of speculation that Tesla's top executives haven't been on the same page when its comes to the car maker's future.

As for Musk buying more stock in the offering, that's par for the course. Tesla is his baby, he had at one point sunk basically his entire fortune in the company (during a crisis in 2008-09), and he needs to demonstrate that he's willing to put a small portion of his considerable net worth on the line to realize his dream of oil-free transportation.

Tesla was trading slightly higher before the markets open on Thursday, after a Wednesday close at $237.