India, Aug. 10 -- US stocks opened mostly flat on Monday as investors remained worried about whether the US and Iran can reach a lasting deal over the Strait of Hormuz. The uncertainty kept investors cautious at the start of the week.

The S&P 500 was up about 0.1%, while the Nasdaq Composite fell 0.1%. The Dow Jones Industrial Average dropped 110 points, or 0.2%, during the session. The three major US stock indexes were coming off their best weekly performance since April. The S&P 500 also ended last week at a record closing high.

The biggest issue for markets on Monday was the uncertainty around the Strait of Hormuz, a key route for global oil shipments.

Iran has said it is getting closer to a deal with Oman that could allow more ship...