The company has devoted resources to autonomous driving rather than developing new models to attract car buyers.

Tesla sales in Europe plunged for a fifth month in a row in May, a blow to investors who had hoped anger toward Elon Musk would have faded by now.

The poor showing is a considerable setback for investors, particularly as it follows Tesla's billionaire CEO, Elon Musk, having previously promised a "major rebound" was imminent. That assurance had recently fuelled a buying frenzy among shareholders.