Elon Musk secretly funded a conservative political group in recent years, according to four people familiar with his donations, illustrating quiet financial support for right-wing causes even before the billionaire entrepreneur in July endorsed former U.S. President Donald Trump¡¯s bid for reelection.

Two of the people familiar with the donations said Musk¡¯s contributions to the organization, Building America¡¯s Future, had started by 2022. One of those people and a third source said the donations amounted to millions of dollars, significantly boosting a group whose advertisements and social media campaigns have criticized the Biden administration and progressive political platforms of the sort Musk himself has increasingly denounced.

It was not possible to determine a precise amount and timeline for the contributions or identify documentation linking the organization¡¯s finances to Musk. Earlier on Wednesday, The Wall Street Journal reported that Musk had financed other pro-Republican groups.