The Dow Jones is down today mainly because investors are reacting to new inflation data showing that prices rose slightly above the Federal Reserve's target in July. The Personal Consumption Expenditures (PCE) index increased by about 2.9% year-over-year, the highest since February, signaling persistent inflation. This has caused concerns about the Federal Reserve's upcoming interest rate decisions and led to some profit-taking after recent record highs. Additionally, major tech stocks like Nvidia and Dell experienced declines due to disappointing earnings forecasts, which contributed to the market's downward pressure. Uncertainty over tariffs and economic growth also adds to investor caution as September approaches, historically a volatile month for markets. In summary, the Dow is down due to inflation worries, profit-taking, and weak tech sector earnings amid ongoing economic uncertainties.