(Bloomberg) -- Soros Fund Management disclosed a stake in an electric-vehicle-battery startup as the billionaire philanthropist’s investment firm raised tech bets and exited its stake in sports betting company DraftKings Inc.

George Soros’s firm said it held $4.6 billion in U.S. stocks at the end of the quarter, an $886 million increase from the prior quarterly period, according to a regulatory filing Tuesday.

Its largest new holding was a $280 million piece of QuantumScape Corp., which is attempting to pioneer solid-state lithium-metal batteries for electric vehicles.

Soros also disclosed that its holding in Palantir Technologies Inc., the controversial data-mining company co-founded by Peter Thiel, ballooned to $435 million at the end of the year after the stock surged 148% during the quarter.

Soros originally revealed it owned 18.46 million shares of Palantir in November but quickly issued a statement saying the original investment was made in 2012 and it regretted the decision.

Read more: Soros regrets early investment in Peter Thiel’s Palantir

“SFM made this investment at a time when the negative social consequences of big data were less understood,” the firm said. Soros explained that it had sold all the shares it’s permitted to sell at the time and would keep selling. “SFM does not approve of Palantir’s business practices.”

A lockup for insiders to sell shares expires this week.

Soros’s early investment in Palantir was converted into publicly traded shares when the company listed on the New York Stock Exchange in September. The firm, which relies on contracts from government entities including the U.S. Department of Defense and the Central Intelligence Agency for much of its revenue, now has a market valuation of $48.5 billion.

Soros, 90, has used his vast wealth to become one of the world’s largest funders of groups promoting justice, democracy, human rights and progressive politics through his Open Society Foundations. He’s poured billions into his philanthropic efforts, and most of his firm’s assets now belong to the foundations rather than to the Soros family.

Over the years the financier’s investments have conflicted with this philanthropic philosophy. His funds have at various times owned stakes in gun manufacturers and coal companies.

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