Is This a Stock Market Melt-Up? Here Are Ways to Tell

The stock market is on a tear again, with high-flying technology stocks propelling the S&P 500 Index toward fresh records and luring swaths of momentum-chasing investors. Speculation that the worst of war in Iran is over has traders piling into artificial intelligence darlings such as Broadcom Inc. and Intel Inc. — and sent semiconductor stocks higher in 21 of the last 23 trading sessions.