PepsiCo Inc. PEP, +0.04% said late Monday it plans to buy BFY Brands Inc., which makes PopCorners snacks, for an undisclosed sum. PepsiCo stock was flat in after-hours trading. PepsiCo said BFY Brands will report to the company’s Frito-Lay North America division. “BFY Brands offers distinctive products that deliver the great taste and ingredients consumers are looking for,” PepsiCo Chief Executive Steven Williams said in a statement. “Their production capabilities will support the growth of our existing, more-nutritious snack brands.” PepsiCo stock has gained 23% this year, as the S&P 500 index SPX, -0.86% rose 24%.