"The simple message is the economy's doing well," Yellen told reporters on Wednesday. "We have confidence in the robustness of the economy and its resilience to shocks."
Indeed, the latest economic data underlined the positive outlook. A Commerce Department report showed housing starts climbed 3 per cent to a seasonally adjusted annualised rate of 1.29 million units in February.
Meanwhile, a Labour Department report showed initial claims for state unemployment benefits slipped 2,000 to a seasonally adjusted 241,000 for the week ended March 11.
"The reports painted a mostly upbeat picture of the economy," Daniel Silver, an economist at JPMorgan in New York, told Reuters.
Shares of Tyson Foods dropped, trading 2.4 per cent weaker as of 1.37pm in New York, after reports that a deadly form of bird flu infected a second commercial chicken flock that supplies the company.
In Europe, the Stoxx 600 Index ended the session with 0.7 per cent increase from the previous close. Germany's DAX Index rose 0.6 per cent, as did the UK's FTSE 100 Index and France's CAC 40 Index.
In the Netherlands, the benchmark AEX Index closed 0.6 per cent higher after Dutch voters did not give Geert Wilders' anti-Islam, anti-European Union Freedom Party the victory he was hoping for. Prime Minister Mark Rutte's Liberal Party comfortably secured the most seats in parliament.
"Dutch voters rejected populism and voted for Europe," Jacob Funk Kirkegaard, a senior fellow with the Peterson Institute for International Economics in Washington, told Bloomberg. "It seems like Rutte's appeal for a 'centrist fightback against Trump and Brexit' was heard."
Bucking the trend, shares of J Sainsbury closed 1.2 per cent lower after the British supermarket chain posted a decline in quarterly sales at its supermarkets and said it is lowering costs to deal with the impact of the slide in the pound following the Brexit vote.
Sainsbury's like-for-like retail sales fell 0.5 per cent in the in the nine weeks ended March 11, excluding fuel, while those of its Argos business gained 4.3 per cent in the same period.
"The market remains very competitive and the impact of cost price pressures remains uncertain," Mike Coupe, Group Chief Executive, said in a statement.