Warren Buffett's Berkshire Hathaway built a $1.6 billion stake in UnitedHealth last quarter, marking one of its last wagers with the investor as CEO.

Berkshire Hathaway has built up sizable investments in a handful of companies, according to a filing released on Thursday.

Detective work points to one stunning conclusion. Buy the stock or an industrial-sector ETF — but get ahead of Berkshire Hathaway’s big reveal.

Warren Buffett secret stock purchase has been kept confidential for months to avoid triggering copycat trades.

Warren Buffett's Berkshire Hathaway is secretly building a substantial position, estimated at nearly $5 billion, sparking widespread speculation. CNBC

UnitedHealth shares surged Friday after Warren Buffett’s Berkshire Hathaway revealed a stake in the embattled healthcare giant. Monitor these major chart levels.

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Leveraged positions in the stock market jumped 18% in one month and topped $1 trillion for the first time. Increasing use of debt to invest can tell us a lot about investors' attitudes. And while this has always been the case,