Elon Musk said on Tuesday he is moving the headquarters of two more of his companies - social media platform X and rocket company SpaceX - to Texas from California, citing a new gender-identity law there as the "last straw."

With these steps, the billionaire, who last week endorsed Republican Donald Trump for U.S. president, will have relocated Tesla and most of the businesses he controls or heads to Texas.

The world's richest man, he changed his own residence in 2021 from California to Texas, where there is no state income tax on individuals.

A new California law that forbids school districts from requiring teachers to notify parents when a child changes gender identity or sexual orientation helped spur Tuesday's announcement, Musk said.

"Because of this law and the many others that preceded it, attacking both families and companies," Musk, who has a transgender daughter, said in explaining the decision on X - formerly Twitter - which he bought in 2022.

The CEO of SpaceX and Tesla in recent years has become outspoken on politics and often criticizes the Biden administration and Democrats' positions on issues including transgender rights and immigration.

California voters have historically supported Democratic candidates while Texas is considered a reliable Republican stronghold.

Musk said SpaceX's main office would move to an existing facility in Boca Chica, Texas, while X would move to Austin. But the extent to which jobs or facilities in California will transfer to Texas was unclear.

SpaceX has a sprawling headquarters near Los Angeles, a major aerospace hub where thousands of employees build the company's workhorse Falcon 9 rocket, Dragon astronaut capsules and some Starshield satellites.

In 2021, Musk moved Tesla's headquarters from California to Texas as well but said last year that California would remain its engineering hub.

He transferred SpaceX’s incorporation from Delaware to Texas earlier this year. This followed a Delaware judge's decision invalidating Musk's $56 billion compensation plan at electric vehicle maker Tesla.

(Reporting by Priyanka.G in Bengaluru; Editing by Maju Samuel and Cynthia Osterman)