Market analysis indicates that despite some traders' concerns about a repeat of the 1987 crash as the "Black Monday" anniversary approaches, US stock futures opened slightly higher on Monday, with Dow Jones Industrial Average contracts up 0.1%. Analysts believe that modern markets have circuit breakers, where a 7% drop in the S&P 500 Index would halt trading for 15 minutes, and a 20% drop would close the market, making a repeat of the Dow's 22.6% single-day decline in 1987 "impossible." Furthermore, current market valuations and corporate earnings growth also differ from the situation back then.