GSK (GSK) stock jumped back into a buy zone Monday after announcing Chief Executive Emma Walmsley will step down at the end of the year. Walmsley has led GSK for nine years and says it's time to hand the reins over to someone new. On Friday, GSK stock closed below that key mark. Haleon Demerger, 'Major New Products'During her tenure, Walmsley separated the consumer health unit into its own company, Haleon (HLN). GSK stock has risen more than 16% this year, but remains slightly off its 2025 intraday high at 45.93, achieved in May.