Check out the companies making the biggest moves in premarket trading: PepsiCo — The snack and beverage giant rose nearly 6% after The Wall Street Journal reported, citing sources, that activist Elliott Management had taken a $4 billion stake in the company. Kraft Heinz — The company confirmed earlier reports that it would split up into two publicly traded companies through a tax-free spinoff. The names of the two new companies will be determined at a later date. One unit, which currently goes by “Global Taste Elevation,” will include Kraft’s shelf-stable products such as Heinz and Kraft Mac & Cheese. The other one, “North American Grocery,” will include brands such as Oscar Mayer and Lunchables. Shares were little changed. Constellation Brands — The stock tumbled 8.3% after the brewer cut its full-year guidance. It now expects earnings to come in between $10.77 and $11.07 per share, down from its prior guidance of $12.07 and $12.37 per share. Signet Jewelers — The jeweler popped 3.8% on better-than-expected results for the second quarter. Signet earned $1.61 per share, excluding certain items, on revenue of $1.54 billion. Analysts polled by FactSet expected a profit of $1.24 per share on revenue of $1.5 billion. The company also increased its full-year earnings guidance. Nio — U.S.-l …
