WASHINGTON/BEIJING (Reuters) -The United States said on Tuesday that 104% duties on imports from China will take effect shortly after midnight, even as the administration of President Donald Trump moved to quickly start talks with other trading partners targeted by sweeping tariffs. S&P 500 companies have lost $5.8 trillion in stock market value since Trump's tariff announcement last Wednesday, the deepest four-day loss since the benchmark was created in the 1950s, according to LSEG data.