A rally in the world’s largest technology companies left stocks at all-time highs amid speculation that artificial intelligence will keep driving earnings for the group that has powered the bull market. While most sectors in the S&P 500 took a breather after a three-day run, the cohort of tech megacaps kept powering ahead. Microsoft Corp. climbed 2% after finalizing a new pact with OpenAI that will give the software giant a 27% ownership stake worth about $135 billion. Apple Inc. briefly topped $4 trillion. Nvidia Corp. plans to make a $1 billion equity investment in Nokia Oyj. On Wednesday and...