US stock markets opened lower on Friday. The three major indexes started the day in the red after investors sold technology stocks. Shortly after the opening bell (9:30 a.m. ET), the S&P 500 fell 0.7%. The Nasdaq Composite dropped 1.1% at the open.US stock market opened lower as OpenAI IPO delay (Bloomberg/Representative image) (Bloomberg)The tech-heavy index was the biggest loser among the three major indexes. The Dow Jones Industrial Average fell 237 points, or 0.5%, soon after trading began. Later in the trading session, losses became smaller. The S&P 500 and Dow traded near the flat line, while the Nasdaq was down about 0.3%.OpenAI IPO delayInvestors became worried after a report said OpenAI may delay its IPO until next year, as per New York Times. The report said OpenAI is thinking about delaying its IPO because of SpaceX's weak stock performance after its market debut and the recent volatility in AI-related stocks.The possible IPO delay raised concerns that AI companies may spend less on expensive infrastructure in the future. JPMorgan traders said the delay in raising money from public markets could make companies rethink whether current AI infrastructure spending is sustainable.AI chip stocks fallChip stocks came under pressure after the report. Investors sold shares of companies linked to AI hardware. Micron Technology shares fell about 2%. Advanced Micro Devices (AMD) also dropped around 2%. Intel shares declined about 2% as well. Oracle shares fell more than 1%. The technology sell-off was even stronger in Asian markets.SoftBank Group, one of OpenAI's major backers, fell more than 12%, leading losses in Asia.