CNBC" Halftime Report" trader Pete Najarian purchased shares of the Market Vectors Gold Miners ETF Thursday for his model portfolio after spotting unusual options activity.
The ETF tracks the performance of the NYSE Arca Gold Miners Index, which consists of large and small gold mining companies. So far this year, the GDX is already up 40 percent.
In other moves, the trader also sold two of his top holdings: Twitter and Starbucks.
Watch the video below to find out why he's bullish on gold mining stocks.