Tesla Inc's (TSLA.O) US$1.2 billion share and convertible debt offering on Friday demonstrates once again the unflagging ability by the luxury electric carmaker and its high-profile head, Elon Musk, to tap Wall Street for sorely needed cash.

In its second such capital raise in the past 12 months, the  Silicon Valley company offered stock and convertible notes, roughly 20 per cent more than it planned but less than what investors had generally been expecting, ahead of the launch of its crucial Model 3 sedan, Tesla's stock was up slightly to US$262.42 in afternoon trade on the Nasdaq.

The capital raise removed "an overhang on the stock," in the eyes of investors, wrote analyst Jamie Albertine of Consumer Edge Research, given uncertainty over how Tesla would meet its robust spending needs, from the Model 3 to its massive battery factory in Nevada.

More broadly, the successful offering underscores the ability of Musk to convince Wall Street over and over of his long-term vision - that Tesla will someday become a carbon-free energy and transportation heavyweight.

Despite facing major financial hurdles, and the dilutive nature of stock sales, the triumphant offering confounds Tesla skeptics, who point to the loss-marking company's US$42.37 billion market capitalization - greater than that of Nissan Motor Co Ltd , which reported a profit of US$4.7 billion last year.

Tesla's plan to spend US$2 billion-$2.5 billion in the first half of 2017 in capital expenditures ahead of the July Model 3 launch left little cushion with US$3.39 billion on the books in cash and cash equivalents at the end of 2016.

"Liquidity and cash burn remain key near-term risks, and investors may grow weary of continued raises as this is the second capital raise in a year," wrote UBS analyst Colin Langan.

The bulk of Friday's offering, or US$850 million, came from convertible senior notes due 2022, with US$350 million raised from the sale of 1.3 million common shares at US$262 apiece.

That was higher than the US$250 million in stock and $750 million in notes the company said it expected to sell.

Musk, already the company's top shareholder with a stake of about 21 per cent as of December, bought 95,420 common shares for US$25 million in the latest stock sale, Tesla said.

The 1.3 million shares sold represents about 0.8 per cent of Tesla's outstanding shares as of Dec. 31.