The market-share gap between the top-selling U.S. electronic cigarettes remained at a status-quo stage with top-selling Juul holding about a 4.8-percentage point gap over R.J. Reynolds Vapor Co.’s Vuse. The latest Nielsen analysis of convenience store data, covering the four-week period ending Jan. 15, determined Juul was at 38.1% market share and Vuse at 33.3%. [...] E-cigarette sales overall have slumped since February 2020, when the Food and Drug Administration implemented its latest round of heightened regulations on the products.