Earlier this month, Nvidia was added to the Dow Jones Industrial Average. It has nearly tripled in value this year -- making it by far the best-performing Dow component in 2024. But when it comes to Dow stocks that have been in the index for longer than just a few weeks, Walmart (WMT 2.02%) takes first prize as the best performer year to date, with a whopping 72.1% gain compared to just a 17.5% gain for the index.Here's what's behind Walmart's breakout year and if the dividend stock is worth buying at its a ...