The S&P 500 jumped the most in nearly two years posting gains of nearly two per cent, after the federal reserve's pledge for "patience" with future rate hikes sparked a global market rally.
It surged 2.4 per cent to 2,061.23 which is it's best daily performance since January last year.
The Dow Jones Industrial Average was up 2.4 per cent to 17,778.15 which was its biggest daily rise since late 2011.
Last night Fed chair Janet Yellen and co. ditched their "considerable time" approach to raising interest rates in favour of "patience" in normalising policy, but later told investors a rate hike wasn't on the way anytime soon.
Despite a worsening global economic outlook Yellen assured markets that the US economy was on track to deliver solid growth in the future.
She also said it wasn't a major concern that some banks may be leveraged and exposed to oil price moves. US and Brent oil have tanked around 50 per cent since June.
Yesterday the S&P 500 scored its best result since October 2013 gaining 2.04 per cent to 2,012.89.