A merger between a rocket company and a carmaker sounds like a thought experiment, yet this week it acquired a formal process. Elon Musk, who runs both SpaceX and Tesla, says each firm has created a special committee to discuss combining the two. No deal has been agreed, and no terms have been announced. But the existence of two committees matters, because it moves the idea from social-media speculation to corporate procedure.

The reason for two separate bodies is structural. Musk sits on both sides of the table, and a transaction in which one person is the dominant decision-maker for buyer and seller creates an obvious conflict of interest. Committees are the standard remedy: in theory, they allow directors without a stake in the outcome to negotiate, test the price and recommend whether to proceed. Governance specialists in New York, London and Singapore generally watch how independent such panels really are, since their credibility often determines whether investors accept the result.

Investors would have the final word. According to Musk, a merger would require the approval of 50% of shareholders. That threshold sounds modest, but the two companies could hardly be more different as investments. Tesla is publicly traded, so its owners can trade freely and voice their opinions daily through the share price.