Elon Musk has opened the door to merging Tesla and SpaceX into a $3.5 trillion (€3.1tn) giant, the latest step in years of folding his companies into one another, with a deal reportedly aimed at closing before US President Donald Trump leaves the White House. The two companies already share Elon Musk, which begs the question of who really benefits from a merger. Key points and original sources are listed below.

• Elon Musk has opened the door to merging Tesla and SpaceX into a $3.5 trillion (€3.1tn) giant, the latest step in years of folding his companies into one another, with a deal reportedly aimed at closing before US President Donald Trump leaves the White House.S1

• The two companies already share Elon Musk, which begs the question of who really benefits from a merger.S2