Tesla stock rises after Elon Musk's masterplan tweet

Tesla's electric cars have been lauded, but the firm has repeatedly missed its production goals

Telsa's shares rose more than 4% in early trade after its chief executive teased a new "masterplan".

Elon Musk tweeted on Sunday that he would issue a follow-up to his original vision for the electric car company.

But he gave no hint as to what it would contain.

In recent weeks, Tesla has had to deal with the crash of one of its cars driving in autopilot mode and controversy over a proposed merger with a solar panel provider led by Mr Musk.

The firm also confirmed it had fallen short of its car production target again.

Mr Musk said he hoped to detail his new masterplan before the week's end

"There's a lot of very enthusiastic Tesla fans that look for a reason to buy this stock," commented Efraim Levy, a Wall Street analyst at S&P Capital.

"The fact that there will be - at least in their minds - potential upside from a new masterplan... is contributing to the rise in the valuation today.

"But on a fundamental basis, I think it's an expensive stock."

Car crash

Mr Musk's original plan was published in August 2006 and detailed how he intended to make a "low-cost family car" that would be more eco-friendly than petrol-based alternatives.

This was eventually revealed as the Model 3 in April of this year. The company has since received more than 400,000 pre-orders for the car.

Although Mr Musk is keeping quiet about what the new plan will detail, he has posted several tweets in defence of his firm's autopilot feature.

The facility allows its cars to automatically steer, change lanes and adjust their speed in response to traffic while driving on motorways.

Earlier this month, Tesla revealed that Joshua Brown, a Model S owner, had died after its software was unable to recognise "the white side of the tractor trailer against a brightly lit sky" that had driven across the car's path in Florida.

The car's manual warns that autopilot cannot always detect other details and it is described as being in "beta".

"Use of word 'beta' is explicitly so that drivers don't get comfortable. It is not beta software in the standard sense," Mr Musk tweeted.

"Point of calling it 'beta' was to emphasise to those who chose to use it that it wasn't perfect."

He added that he expected it would take another half a year until the system had clocked up more then one billion miles of use outside of Tesla's labs.

He added: "1B needed for min statistical sample size. More software mods and data may be needed beyond that."

A Tesla driver died in Florida in May after colliding with a lorry

Last week, the automaker denied suggestions that the feature had caused a second car crash in Pennsylvania.

"Based on the information we have now, we have no reason to believe that autopilot had anything to do with this accident," it said.

Musk's merger

Mr Musk has also faced criticism for planning to combine Tesla and SolarCity.

He is both the chairman of the solar panel firm and one of its biggest shareholders.

Investment manager Jim Chanos has described the idea as being "shameful", claiming the tie-up would cause great stress to both businesses.

But Mr Musk defended the idea saying it would help to create "a seamlessly integrated Tesla battery and solar panel product that looks beautiful".