Fuel for the feud was provided by the fact that X/Twitter itself has a long memory — an archive that Bluesky et al will always struggle to match. Musk, furious that Trump's "big beautiful bill" would increase the deficit, started posting quote tweets of every time Trump had promised to lower it, adding snarky comments in agreement.

Shares dropped on Thursday as Musk publicly criticised the tax bill the US president is pushing to enact into law.