Tesla (TSLA) Chief Executive Elon Musk raised plenty of eyebrows on the company’s conference call Wednesday, and they likely inched higher this morning following his tweet storm in which he defended his remarks and hit out against short sellers.

That hasn’t stopped bears: Short interest in the stock increased by nearly 400,000 shares on May 3, the day after the report, bringing the total to more than 40 million shares for the first time in Tesla’s history, notes S3 Partners’ Ihor Dusaniwsky. Moreover, despite Musk’s remarks...