Mixed US Stock Market Performance in Late August 2026

The US stock market experienced mixed results in late August 2026, according to Morningstar's data. The Dow Jones Industrial Average (DJIA) saw a small decline of 0.2% over the past five days, while the S&P 500 index rose by 1.1%. The NASDAQ composite index also increased by 2.1% during this period.

On the other hand, Morningstar's US Total Market and Wide Moat Focus indexes both decreased by 0.5% and 0.7%, respectively. However, the global markets were more positive, with a 1.3% gain in the large-cap segment and a 2.4% increase in the mid-cap segment.

Among individual stocks, Moderna (MRNA) shares surged by over 100% after the company's mRNA cancer vaccine showed promising results. The stock price rose to $152.42 as of August 19, 2026. Merck & Co Inc (MRK), on the other hand, saw its large late-stage pipeline building a solid defense against Keytruda's patent cliff.