Tesla Motors chief executive officer Elon Musk says the proposed acquisition of SolarCity Corp could eventually push the electric car maker's valuation to $1 trillion, but investors were sceptical. Shares of Tesla were down nearly 7 per cent at $204.50, putting its market capitalisation at $29.8 billion (€26.408bn).

The much smaller SolarCity was up nearly 9 per cent at $23.01 (€20.39), valuing the US market leader in residential rooftop solar panels at $2.2 billion (€1.95 bn).

Tesla on Tuesday offered to buy SolarCity in a stock deal worth as much as $2.8 billion ($2.481 bn).

“I have no doubt about this - zero,” Musk, a major shareholder of both companies, said on a conference call with analyst before markets opened on Wednesday. “We should have done it sooner.”

- (Reuters)