Former President Donald J. Trump and Tesla CEO Elon Musk, shown in these file photos. David T. Foster III and Patrick Pleul, AFP/FileWASHINGTON -- Billionaire Elon Musk has donated almost $75 million to the political action committee he created to support Donald Trump's US presidential campaign, according to filings made late Tuesday, illustrating the Tesla founder's growing commitment to the Republican's cause.

Musk, estimated to be the world's richest man, has taken an increasingly visible role in Trump's campaign, accompanying him on stage at a recent rally in Pennsylvania and frequently lambasting his opponent, Democrat Kamala Harris, on social media.

Trump frequently name-checks Musk at rallies, and has promised to appoint him to a committee tasked with slashing government bureaucracy.

Harris and Trump are locked in a too-close-to-call race for the White House, according to polls.

Musk's America PAC has raised $74.95 million for Trump's cause in the period between July 1 and September 30, according to filings with the Federal Election Commission.

The PAC has focused on launching grassroots get-out-the-vote efforts, including in battleground states such as Pennsylvania that tip the overall national election result.

On its website, America PAC offers those who sign up to help with voter turnout "$30 per hour, with bonuses for performance."

Musk earlier said he would pay $47 to anyone who gets a registered swing-state voter to sign a petition supporting free speech and the right to bear arms.

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The billionaire endorsed Trump after the Republican survived an assassination attempt in July.

In the same reporting period, Harris's primary Harris Victory Fund PAC hauled in $633 million, according to its FEC filing.

Harris dramatically entered the race for the presidency after the withdrawal of incumbent President Joe Biden, following a disastrous debate performance against Trump in July.

Since then, the current vice president has reinvigorated the party's base and carried out a barnstorming campaign across the country, with a particular focus on battleground states.

Her political action committee's year-to-date receipts were nearing a billion dollars, the filing said, standing at $931.2 million.

© Agence France-Presse