Trembling! US tech stocks stumble at the beginning of earnings season, Tesla and Netflix stock prices plummet.

The tech giants that have dominated the U.S. stock market this year have been reporting their latest quarterly results, however, the leading Tesla (TSLA.US) and Netflix (NFLX.US) have not delivered results that satisfy investors. Zhitong Financial APP learned that Tesla's second-quarter revenue increased 47% year-on-year to $24.9 billion, and earnings per share excluding some items were 91 cents, which was better than market expectations. But gross margin was 18.2 per cent, slightly below Wall Street expectations of 18.8 per cent, well below the 25 per cent a year earlier and down from 19.3 per cent in the previous quarter. Operating margins fell to a new low of 9.6 percent in at least five quarters, partly due to incentives and discounts. Netflix's second-quarter revenue of $8.19 billion billion was lower than analysts' expectations of $8.3 billion, and third-quarter revenue is expected to grow 7.5 percent year-on-year to $8.52 billion, but this guidance is still below market expectations of $8.67 billion, dragged down by exchange rate fluctuations and lower subscription fees in some regions. Naifei's crackdown on password-sharing operations and ad-supported subscription services are beginning to bear fruit, with a net new paid users of 5.89 million in the second quarter, not only significantly higher than the level of the first quarter, but also much higher than the 2.07 million expected by the market, and the best second-quarter user growth rate since the epidemic. In the context of the current high valuation, investors are looking more closely at this earnings report. Tesla fell more than 4 percent after the earnings report, Nai Frisbee fell more than 8 percent after the report, and other star technology stocks also fell slightly, dragging Nasdaq 100 stock index futures down about 0.7 percent. The Big Seven now account for 26% of the total market capitalization of the S & P 500, up from 20% at the beginning of the year. These companies include Apple (AAPL.US), Microsoft (MSFT.US), Amazon (AMZN.US), Nvidia (NVDA.US), Tesla, Alphabet(GOOGL.US) and Meta(META.US), with a combined market cap of more than $11 trillion. Without the rise in these stocks, the overall market would be much weaker. What's more, driven by the AI boom, these companies are currently trading at a huge premium to other companies in the market-an average price-to-earnings ratio of 38 times, compared with 20 times for the S & P 500 as a whole. In essence, U.S. stocks face two major problems: they can easily disappoint investors because of the high expectations of these technology companies; if the performance of technology companies does disappoint investors, their size means that the market may be dragged down. Volatility in the share prices of several large companies can have a significant impact on the value of 401(k) pension plans in the United States, as well as the ability of other companies to raise capital. In fact, investors are not usually so concerned about the company's spring results. The last three months of the year tend to be the most important: It's a time when Apple sells the most iPhones, people are shopping for their holidays on Amazon, and brands are running ads on Google and Facebook in an attempt to attract shoppers. However, chipmaker Nvidia said in May that revenue for the three months to June would be about 53% higher than analysts' expectations, partly due to the artificial intelligence boom. This drove a sharp rise in Nvidia's stock price, making it the first chipmaker with a market value of $1 trillion. Other big tech stocks also rose. Since then, investors have been watching second-quarter results closely. To justify their high valuations, companies may have to hand over better-than-expected results and offer an equally upbeat outlook for the next few quarters, Bloomberg Intelligence equity strategist Laurent Douillet said. "Some of these companies are up 50 to 60 per cent in the last few months," he said. "There comes a time when they need to deliver on their promises." Nasdaq is also aware of the problem of over-concentration in the market. On July 24, the Nasdaq 100 Index component weights will be adjusted, a move that many expect will diminish the tech giants' huge influence over the index. It is worth noting that sometimes, even if a company reports good financial results, its stock will still take a slight hit the next day. For example, in 2020 and 2021, Apple's earnings exceeded analysts' expectations in seven of the eight quarters, but six of those quarters still saw a decline in the stock price. This is because investors often take advantage of this opportunity to take profits. The real concern is that there could be more tech giants with disappointing results. If Meta's advertising performance is weaker than expected and Microsoft's artificial intelligence product adoption is not as fast as expected, the market may suffer more.