How long can this nirvana last for investors? The stock market keeps methodically ticking into record territory, and the Dow Jones industrial average is trading above 23,000 for the first time. It’s been nearly 16 months since S&P 500 index funds had a pullback of even 5 percent over the course of days or weeks, its longest such streak in two decades. Many analysts expect the market to keep climbing, at least for the next year.