TESLA’S shares have been tumbling after the electric vehicle maker posted a record first-quarter loss and its CEO got testy at times during a conference call.

Tesla tore through $US745.3 million ($993 million) in cash in the quarter, due largely to the slow production ramp-up of the Model 3 mass-market electric sedan.

Mr Musk fired up when money management firm Bernstein’s senior analyst Toni Sacconaghi, questioned the profitability of the upcoming Tesla 3.

“Excuse me. Next. Boring, bonehead questions are not cool. Next?” he said.

When Joseph Spak, an analyst from RBC Capital Markets, followed up about the Model 3, Musk reportedly paused for 15 seconds, before adding: “These questions are so dry. They’re killing me.”

He then allowed multiple questions from Galileo Russell, host of YouTube channel HyperChange TV, which has around 9300 subscribers. After 20 minutes of questions from Russell, Mr Musk thanked him for his “great” questions.

RBC Capital Markets’ Joseph Spak called it an “odd conference call that lacked answers to questions on investors’ minds and overshadowed earnings.”

“The general sentiment was that the defensiveness spoke volumes,” he added in an analyst note.

Shares dropped more than 7 per cent in premarket trading, or a los of about $US2 billion ($2.6 billion).