Wall Street has graduated to the longest-ever "bull market", a run that began amid extraordinary crisis-era monetary policy and which experts think could persist at least a while longer. US President Donald Trump cheered the news after the S&P 500 yesterday closed for the 3,453rd straight time without a drop of 20 per cent over the more than nine-year stretch. "Longest bull run in the history of the stock market. congratulations America!" Trump said on Twitter shortly after the closing bell.

The marathon run comes amid signs the US economy has accelerated this year after a long period of slow but steady growth. Experts say trade wars and higher interest rates are among potential threats to the persistence of the bull run. Market watchers liken the landmark to other stock market records, such as when the Dow hit 25,000 points for the first time. Investing in stocks remains concentrated among the wealthiest, with many Americans still hesitant to buy stocks following the 2008 financial crisis.