Elon Musk clandestinely funded a conservative political group in recent years, according to four people aware of his donations, illustrating quiet monetary support for right-wing causes even before the billionaire tech magnate in July endorsed former President Donald Trump’s bid for re-election.

Two of the people acquainted with the donations shared that Musk’s contributions to the organization, Building America’s Future, had begun by 2022. One of those people and a third source divulged that the donations amounted to millions of dollars, giving significant boost to a group whose advertisements and social media campaigns have panned the Biden administration and progressive political platforms of the kind that Musk himself has increasingly condemned.

Reuters tried but was unable to fix a precise amount and timeline for the contributions or identify documentation relating the organization’s finances to Musk. Earlier on Wednesday, The WSJ (Wall Street Journal) reported that Musk had bankrolled other pro-Republican groups. Neither Musk nor any spokesperson for Building America’s Future replied to emails seeking comment.

The tech magnate behind ventures including space contractor SpaceX, electric carmaker Tesla and the social media platform X, Musk for many years was extra cautious to avoid suggestions that he favored either major U.S. political party. As lately as March, months before he publicly backed Trump and announced plans to fund a political action committee to work against Democrats, he posted on social media: “Just to be super clear, I am not donating money to either candidate for US President.”

Donations to Building America’s Future, nevertheless, would show he was already utilising his vast resources to bankroll right-wing causes. As a non-profit 501(c)(4) group, the organization isn’t required to disclose its financial backers under federal law. While such groups aren’t permitted to finance candidates’ political campaigns, they can espouse political causes. As such, they are generally referred to as “dark money” groups – used by political operatives, Republicans and Democrats alike, to hide the financial origins of influence campaigns.

In Musk’s case, the four people aware of his donations divulged, the contributions to Building America’s Future remained closely guarded. Three of the people were informed about the donations by executives at or allied to the organization and the fourth was consulted on the matter by a Elon Musk aide.

Revenues at Building America’s Future, as per the government data, mounted from some $11 million in 2021 to about $53 million in 2022, the year two of the people divulged Musk had already started his donations. The figures are the most recent accessible from the Internal Revenue Service, which requires tax-exempt establishments to disclose their revenues.