Donald Trump bought up to $50,000 of SpaceX stock on 23 June, roughly a fortnight after the company completed the largest initial public offering in history, according to a financial disclosure reported this week.

The purchase places the sitting president on the shareholder register of a company whose federal contracts and regulatory treatment his own administration determines, an arrangement the conflicts around the listing had already made a live question.

The White House has offered a procedural explanation rather than a defence of the position itself. A spokesman said the president’s portfolio is managed by third-party financial institutions and replicates recognised indexes, naming the Schwab 1000 as an example.

That explanation is plausible on its face, and it points at something structurally odd about this particular stock. SpaceX lobbied the major index providers to accelerate its inclusion before going public, which means a great many investors now hold it without having chosen to.

Anyone tracking a broad US index acquired exposure to SpaceX automatically, and a portfolio built to replicate one would have bought in around the time the disclosure records. Whether the president personally directed the purchase is a different question from whether it appears on his disclosure, and the document itself cannot settle it.