The Dow Jones Industrial Average on Monday was set to end at the lowest level in about 15 months, amid a broad-market selloff on Christmas eve. The Dow DJIA, +0.19% had fallen below 21,987, retreating below 22,000, a psychological round-number level first achieved back in August of 2017. The last time the Dow was below 21,000 was early September, according to FactSet data. Most recently, the Dow was down 460 points, or 2.1%, at 21,983, the S&P 500 index SPX, +0.29% was off 1.9% at 2,369, while the Nasdaq Composite Index COMP, +0.36% retreated 1.2% at 6,253. U.S. stocks will end at 1 p.m. Eastern and will be closed on Christmas on Tuesday, along with other major indexes.