Contrition pays off -- just ask Elon Musk.

The Tesla Inc. (TSLA.O) chief executive officer began the question-and-answer portion of the carmaker’s second-quarter earnings call by atoning for what he called his “bad manners” three months earlier. Musk then took the first two questions from two analysts he was harshest with last quarter -- Sanford C. Bernstein’s Toni Sacconaghi and RBC Capital Markets’ Joseph Spak -- and offered personal apologies.

In the first-quarter call in May, Musk cut off Sacconaghi for what he called “boring, bonehead” questions and said Spak’s questions were “so dry.” On Wednesday’s call, Musk apologized to Sacconaghi for being “impolite” before and blamed insufficient sleep.

It was a major mea culpa to Wall Street by a billionaire who in recent weeks called a British cave diver in the Thai rescue mission a pedophile and portrayed a former battery factory employee as a saboteur. Musk was urged last month by major shareholder Baillie Gifford & Co. and bullish venture capital firm Loup Ventures to focus on execution.

Investors responded very positively: Tesla shares surged as much as 12 per cent in after-hours trading.