U.S. stock futures opened lower at the beginning of September, with Dow futures dropping 300 points amid concerns over rising oil prices and increasing bond yields. The S&P 500 and Nasdaq also experienced declines as investors reacted to inflation fears linked to higher oil costs and Treasury yields. Historically, September has been a challenging month for stocks, and analysts are watching closely as Wall Street braces for a potentially weak start. The situation is further complicated by ongoing geopolitical tensions and economic indicators that could influence market movements in the coming days.