(Updates paragraphs 1, 5, 6)

July 1 (Reuters) - U.S. President Donald Trump on

Tuesday called for a review of subsidies awarded to Elon Musk's

companies, sparking fears of tougher regulatory scrutiny across

the billionaire's ventures in the transportation, energy and

space sectors.

Below is a list of U.S. regulators who oversee Musk's

companies, including automaker Tesla, rocket and

satellite company SpaceX, brain implant company Neuralink,

social media platform X and construction firm The Boring

Company.

National Highway Traffic Safety Administration

Tesla faces ongoing oversight from U.S. auto safety

investigators about the safety of its vehicles especially when

using advanced driver assistance systems.

Last month, the regulator asked the EV maker for more

information after reviewing online videos of a robotaxi

allegedly using the wrong lane and of speeding by another

driverless vehicle, shortly after Tesla launched a limited, paid

robotaxi test service in Austin, Texas.

The agency is reviewing the responses to its questions about

the safety of the robotaxi in poor weather among numerous

issues.

The NHTSA has been investigating Tesla's full self-driving

collisions in reduced roadway visibility conditions since

October.

Federal Communications Commission

The Federal Communications Commission in April voted to open

a review of the decades-old spectrum sharing regime between

satellite systems sought by SpaceX. SpaceX wants access to new

spectrum from the FCC in the coming years to speed deployment of

satellite-based internet service.

The review by the U.S. telecom regulator aims to allow a

greater and more intensive use of spectrum for space activities.

Existing reductions approved in the 1990s limit power usage that

prevent better coverage from SpaceX's Starlink and other

systems.

Food and Drug Administration

The FDA oversees the clinical trials for Neuralink, Musk's

brain implant company, deciding whether such trials can take

place and whether Neuralink can eventually sell its device to

consumers. The agency already approved such trials in the U.S.

Neuralink has also been pursuing clinical trials outside the

U.S, including in Canada.

The FDA had initially rejected Neuralink's request to start

clinical trials, citing safety risks, Reuters reported in 2023.

The agency has since given the startup approval to do clinical

trials, which are ongoing.

Environmental Protection Agency

SpaceX faces environmental regulations from the EPA, which

oversees the company's wastewater discharges at its operating

site in Texas.

The company's operations are also subject to environmental

reviews under the National Environmental Policy Act, with

several agencies including the Fish and Wildlife Service

required to analyze the impact of the company's rocket launches

and landings on land, water and wildlife.

Federal Aviation Administration

In September, the FAA proposed a $633,000 fine against

SpaceX for failing to follow license requirements in 2023 before

two launches. That investigation remains open. The FAA could

also impose new restrictions or additional scrutiny after a

series of explosions of SpaceX launches.

Securities and Exchange Commission

Musk is embroiled in litigation with the SEC over his 2022

takeover of Twitter, with Musk now due to respond to those

allegations this month.

The regulator also had opened an investigation into his company

Neuralink according to a December letter from Musk's lawyer he

posted on social media platform X.

Federal Trade Commission

The FTC is a consumer protection agency that ensures social

media companies like Musk's platform X protect children's

privacy and safeguard Americans' data.

The FTC, which also enforces antitrust law, recently opened

a probe into coordination between media watchdog groups, some of

whom Musk has accused of orchestrating an illegal group

advertiser boycott against his social media site.