Getty Images; Jenny Chang-Rodriguez/BIThe two-year-old bull market in stocks could last for another year, NDR strategists said. That's assuming three positive catalysts fall into place, they added.Median gains in the third year of a bull market are about 13%, the firm said in its analysis.The latest bull market in stocks may still have a long life ahead of it, according to Ned Davis Research.Strategists at the research firm said that the two-year-old bull run could potentially last for another 12 months.