Stock market today: Dow, S&P 500, Nasdaq fall amid sharp GDP expansion, jobless claims dip

Market Overview - US stocks experienced a decline, with the Dow Jones Industrial Average dropping 0.2%, the S&P 500 losing approximately 0.4%, and the Nasdaq Composite sliding around 0.5% [2] - The recent record-breaking rally in stocks is facing challenges due to debates over whether AI enthusiasm is inflating valuations excessively [2] Economic Indicators - Jobless claims in the US decreased to 218,000 for the week ending September 20, down from 232,000 previously, indicating a positive sign for the labor market [3] - Continuing claims also saw a slight decline to 1.92 million [3] - The US second quarter GDP rose to an annualized pace of 3.8%, rebounding from a 0.6% decline in Q1 and surpassing estimates of 3.3% growth [4] Corporate Updates - Costco is anticipated to report its quarterly results, with expectations of a significant increase in sales as consumers seek deals amid economic uncertainty [5]