Dow Jones, S&P 500 and Nasdaq today June 29: The US stock market kicked off the shortened trading week with strong gains, led by technology shares, as the Dow Jones Industrial Average closed above the 52,000 mark for the first time.US Stock Market Today: Dow Jones Closes Above 52,000 for the First Time, S&P 500 and Nasdaq GainThe Dow climbed 306.63 points, or 0.59%, to close at 52,182.74, the S&P 500 gained 1.18% to close at 7,440.43, while the Nasdaq Composite advanced 2.07% to end at 25,820.14, as per a CNBC report.US Stock Market June 29: Alphabet Leads Market Gains in Dow DebutAlphabet was among the biggest gainers of the day, rising nearly 5% during its first trading session as a member of the Dow Jones Industrial Average.Comcast also posted strong gains, with its shares jumping 4.4% after announcing plans to separate its media and technology businesses into two publicly traded companies. The company expects the spin-off to be completed in about a year, as per the CNBC report.Semiconductor Stocks Stage a Strong ComebackChip-related stocks rebounded sharply after an early-session decline.You Might Also Like:The VanEck Semiconductor ETF (SMH) gained more than 3%, while Astera Labs surged about 16%. KLA climbed roughly 12%, and Applied Materials rose nearly 11%, helping drive the broader technology rally.Holiday Week and Quarter-End Activity in FocusWall Street entered a shortened trading week ahead of the Independence Day holiday, with U.S. markets scheduled to remain closed on Friday.Joe Tigay, a portfolio manager at Equity Armor Investments, explained that, lighter trading volumes during the holiday week could result in larger-than-usual market moves, as per the CNBC report. He also said that, "We also have the end of quarter happening soon, which can cause some window dressing to happen, so advisors are wanting what they report on their quarterly statements to look attractive to their clients, and they’ve been locking in some gains too. A lot of big names have had really big gains so far this year, so locking them in right now… a lot of advisors are happy to do so,” as quoted by CNBC.Geopolitical Developments Remain on Investors' RadarInvestors also monitored developments in the Middle East after the United States and Iran agreed on Sunday to pause hostilities and allow commercial vessels to move freely through the Strait of Hormuz.You Might Also Like:According to a US official, technical discussions under the memorandum of understanding are expected to continue while both sides temporarily stand down. The US official said, “Technical talks are slated to continue on all areas of the MOU,” adding, “Both sides will stand down for now and vessels can move freely,” as quoted by CNBC.The agreement followed weekend military exchanges, including US strikes on Iranian military targets in response to Iranian attacks in the Strait of Hormuz. US president Donald Trump later said on Truth Social that “United States aircraft just struck Iranian missile and drone storage locations, and coastal radar sites, for violating the Cease Fire Agreement, AGAIN!”Why Oil Prices Move HigherCrude oil prices rose as traders evaluated whether the pause in hostilities would reduce concerns over disruptions to global energy supplies.Brent crude climbed 1.6% to $73.15 per barrel, while West Texas Intermediate futures gained 2.2% to settle at $70.75 per barrel.You Might Also Like:S&P 500 Stocks Reach New Highs Than LowsA total of 28 stocks in the S&P 500 traded at new 52-week highs during Monday's session.Among them were Live Nation Entertainment, Airbnb, M&T Bank, AbbVie, Johnson & Johnson, Eli Lilly, Applied Materials, Corning, Palo Alto Networks, and NiSource.By comparison, only seven stocks touched new 52-week lows, including AT&T, T-Mobile US, CME, Intercontinental Exchange, Boston Scientific, Copart, and Rollins.FAQsWhy did the Dow Jones reach a record close?The index gained more than 300 points during a broad market rally led by technology stocks.Why did Alphabet shares rise?The stock gained nearly 5% during its first day as a Dow Jones member.