(For a Reuters live blog on U.S., UK and European stock markets, click LIVE/ or type LIVE/ in a news window.) * IBM tumbles after missing quarterly revenue estimates * AT&T rises as it adds more wireless subscribers * Indexes: Dow down 0.15%, S&P off 0.04%, Nasdaq up 0.19% (Updates prices throughout) Oct 21 (Reuters) - U.S. stock indexes remained subdued on Thursday as losses in IBM pressured technology stocks, with investors focusing on the impact of supply chain disruption and labor shortages on corporate profits. The Dow Jones Industrials Average retreated after hitting an intraday record high in the previous session, while the benchmark S&P 500 index was just about 15 points short of from its early September record. “Stocks are climbing to new highs and anytime the market is trading at or near its all-time high, it is not unusual to see a little bit of more intraday volatility...and it should not concern investors,” said Tom Mantione, managing director, UBS Private Wealth Management in Stamford, Connecticut. Eight of the 11 major S&P 500 sectors were trading lower, with technology stocks weighing the most. IBM tumbled 6.8% after it missed market estimates for quarterly revenue as its managed infrastructure business suffered from a decline in orders. Investors are keeping a close eye on growth outlook from companies facing rising costs, labor shortages and supply chain disruptions, with analysts expecting profit of S&P 500 companies to rise 33.7% from a year earlier, according to Refinitiv data. “Large parts of the S&P are not going to be impacted - software, healthcare, real estate, utilities, energy, materials, financials would not see any of that as an issue,” Mantione said. Tesla Inc erased early declines to rise 2.4% as investors digested the EV maker’s upbeat earnings, despite the company warning of supply-chain hurdles. Other mega-cap stocks including Facebook Inc, Apple Inc and Amazon.com Inc were mixed by early trading. Data showed the number of Americans filing new claims for unemployment benefits dropped to a 19-month low last week, pointing to a tightening labor market, though a shortage of workers could keep the pace of hiring moderate in October. At 9:51 a.m. ET, the Dow Jones Industrial Average was down 53.81 points, or 0.15%, at 35,555.53, the S&P 500 was down 1.72 points, or 0.04%, at 4,534.47 and the Nasdaq Composite was up 28.53 points, or 0.19%, at 15,150.20. AT&T Inc rose 0.7% after the telecom operator’s quarterly revenue and monthly phone bill paying subscriber additions beat market expectations. American Airlines rose 1.5% after posting a smaller-than-expected quarterly loss, while Southwest Airlines Co edged 0.4% lower even as it posted a smaller third-quarter loss. HP Inc gained 5.6% as brokerages raised their price targets on the stock after the personal computer and printer maker forecast upbeat fiscal 2022 adjusted profit and raised its annual dividend. Advancing issues outnumbered decliners by a 1.03-to-1 ratio on the NYSE and by a 1.34-to-1 ratio on the Nasdaq. The S&P index recorded 38 new 52-week highs and no new low, while the Nasdaq recorded 58 new highs and 11 new lows. (Reporting by Shreyashi Sanyal and Devik Jain in Bengaluru; Editing by Arun Koyyur)