Elon Musk and Donald Trump are fighting publicly over several key issues, primarily centered around politics and policy disagreements:

• The main recent conflict started when Musk criticized Trump's extensive tax and domestic policy bill, called the "One Big Beautiful Bill Act," for its massive spending and impact on the national debt. Musk called it "disgusting" and opposed it strongly, even warning about forming a new political party ("America Party") if the bill passed.
• Trump retaliated by threatening to use the Department of Government Efficiency, which Musk helped create, to scrutinize the subsidies and government contracts benefiting Musk's companies like SpaceX and Tesla. Trump even suggested the possibility of cutting off these subsidies and hinted at deportation threats.
• The feud escalated on social media with Musk accusing Trump of appearing in undisclosed "Epstein files" related to convicted sex offender Jeffrey Epstein, a claim dismissed by the White House.
• Musk announced launching the "America Party" as a new third political party aimed at unseating lawmakers who supported Trump's spending bill, which Trump called "ridiculous" and dismissed as confusing to the system.
• The conflict represents a sharp fallout after Musk had previously been a key Trump ally, adviser, and donor. Their relationship deteriorated rapidly after Musk left his government role and vocally opposed Trump's policies.
• Trump also publicly insulted Musk, calling him "off the rails" and threatening serious consequences if Musk funds Democrats. There have been mutual public insults and a complete breakdown of their alliance.
• Musk has removed some of his more extreme posts but continues to criticize Trump and his policies, while Trump has threatened to investigate Musk's government contracts and revoke them.

In summary, their fight stems from profound political and policy disagreements, public personal attacks, and Musk's attempt to create a political alternative to challenge Trump's agenda and allies. The feud is marked by threats over government contracts, accusations of misconduct, and the launch of a competing political party by Musk.