By Nichola Groom

(Reuters) - Leave it to Elon Musk to make a company's stock jump nearly 5 percent a day after reporting widening losses - all in the middle of a market selloff.

Musk's electric vehicle startup, Tesla Motors Inc, on Wednesday posted its eleventh straight quarterly loss, when analysts had expected a profit. Tesla also said it planned $1.5 billion in capital spending this year but had just $1.2 billion in the bank.

Investors focused instead on Musk's promises to make Tesla profitable this year and to deliver 60 percent to 80 percent more vehicles than last year. Analysts described the forecasts as ambitious but not impossible.

It's precisely that outsized optimism that defines Musk and his appeal to the market, despite blown deadlines and long waits for profits in high-risk industries. Musk's two other ventures, SolarCity Corp and Space Exploration Technologies, also face steep challenges in cutting-edge industries.

"Investors look at Elon, and some say he's a promoter or that he steps over bounds with what he promises," said Robert W. Baird analyst Ben Kallo. "But his track record is pretty good. That's why he still attracts the type of institutional investors he does."

Still, at least six analysts slashed their price targets on Tesla shares. Kallo has a "neutral" rating on Tesla and lowered his price target to $230 from $282 on Thursday.

Tesla's stock rose 4.7 percent to $150.47 on Thursday and was among the Nasdaq's top percentage gainers in a weak overall market.

But the gain comes after steep losses so far this year. The automaker's shares are down more than 37 percent - and Musk's personal stake in Tesla has fallen by more than $3 billion.

Barclays analyst Brian Johnson called Tesla "one of the most polarizing stocks." Some investors seem to ignore short-term stumbles and see only a future vision of massive profits from disruptive technology. Others see delays and disappointing results as emblematic of the company's inability to deliver on Musk's soaring rhetoric.

The company lost credibility with some investors after repeated delays of its Model X sport utility vehicle, which Tesla still struggles to produce fast enough for waiting customers. In a Wednesday earnings call, Musk acknowledged the automaker's ambitions for the X outpaced its development and manufacturing capabilities.

"I do think there was some hubris there with the X," Musk said, explaining that the company erred in trying to pack too many features and new technologies into the vehicle.

Both Tesla and SolarCity are trying to revolutionize industries dominated by entrenched and deep-pocketed companies. SpaceX faces different but no less daunting challenges in trying to innovate with reusable rockets.