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Over the last two quarters, Ackman has built two new significant positions for Pershing Square -- Nike (NYSE: NKE) and Brookfield (NYSE: BN) -- piling an estimated $2.2 billion into those stocks during the third quarter alone. Here's why.

Unsurprisingly, billionaire investor Bill Ackman added to his position in footwear giant Nike (NYSE:NKE) during the last quarter. As to whether Ackman is finished building his position remains the multi-billion-dollar question.

Diversification, schmiversification. That seems to be the attitude of billionaire hedge fund manager Bill Ackman. His Pershing Square Capital Management owns a total of 10 stocks. Two of those stocks are different share classes of the same company -- Alphabet.