Elon Musk is testing the limits of legal and ethical restrictions on the role of special advisers in U.S. presidential administrations, according to some legal experts and lawmakers who oppose the billionaire's mission against what he deems wasteful government spending.

Elon Musk is rapidly consolidating control over large swaths of the federal government with President Donald Trump 's blessing, sidelining career officials, gaining access to sensitive databases and dismantling a leading source of humanitarian assistance.

Several of Elon Musk's businesses, including SpaceX and Starlink, have lucrative contracts with the US government, and there is growing concern among many that the billionaire will use his influence on Trump to enrich himself even further and also loosen restrictions that could affect his interests.