Warren Buffett’s Berkshire Hathaway has spent another $54 million to purchase Sirius XM stock, giving it a stake of more than 35% in the satellite-radio company.

Berkshire Hathaway first bought Apple ( AAPL 1.86%) shares in the first quarter of 2016. That was a wildly successful decision, as the "Magnificent Seven" stock has soared 797% since the start of that year (as of Jan. 31).

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