Billionaire financier George Soros, known for donating to liberal causes, now commands one of the most powerful philanthropies in the United States after having moved $18 billion of his personal wealth into his Open Society Foundations.

The philanthropy, launched in 1979 with scholarships to black South Africans under apartheid, supports efforts to promote justice and equality around the globe. The latest contribution vaults the charity into one of the biggest in the United States, behind those such as the Bill and Melinda Gates Foundation, founded by the Microsoft billionaires.

"This is huge news, because he grants in a more political fashion that almost all of his peers," said Eileen Heisman, chief executive of the National Philanthropic Trust, which sponsors donor-advised funds. "This is just going to put more dollars behind it."

Soros ranks 20th on Forbes Magazine's list of the 400 wealthiest Americans with a net worth of $23 billion. The 87-year-old hedge fund manager was born in Hungary but fled the communist country and put himself through the London School of Economics while waiting tables and working as a railway porter.

Through a spokesman, Soros declined to comment.

The Open Society Foundations network has given away $14 billion since 1984.

"We have no plans to change our spending," said Laura Silber, the foundation's head of communications. "We plan to continue to focus on building open societies. That means advancing human rights, advancing justice and democratic practices."

Sources close to the Soros foundation, who spoke on the condition of anonymity because they were not authorized to comment publicly, said that for years, Soros has been migrating his billions in personal wealth from his investment vehicle, Soros Fund Management, to the foundation.

"It's not like he wrote a check for $18 billion and went over and deposited it in the foundation," said one source. "This has been a years-long process."

The news of the $18 billion gift was reported earlier in the Wall Street Journal.

Soros began Soros Fund Management in 1969 and became one of the world's most successful investors, known for speculating on currencies. He is best known for short selling the British pound in 1992, which earned him the name "The Man Who Broke the Bank of England."

In 2011, Soros Fund Management converted its investment fund into a so-called family office that handles Soros's money and that of his foundation.

Soros is known for his long support of progressive causes and U.S. Democratic candidates, making him a frequent target of political conservatives. He was a strident critic of then-president George W. Bush and made personal donations to several nonprofit groups that opposed Donald Trump. He was an early supporter of Barack Obama and gave millions to Hillary Clinton's 2016 presidential campaign.

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The Open Society Foundations has offices in New York, London, Budapest and Brussels. The foundation now works in more than 140 countries, has a staff of 1,500 and commands a $940 million budget.

The largest share of its money — 28 percent — goes toward democratic practices and human rights. Twenty-three regional and national foundations run by local boards help determine how Open Society's grants are distributed.

"He is an immigrant who came from a place where communication and having a dialogue wasn't welcome," Heisman said. "He lived under communism and under Nazi occupation. Living in an open society is important to him, and his grant-making has followed that path for years."