Tech stocks lead Wall Street higher as Yellen testifies

Wall Street rose on Wednesday, with S&P 500 rebounding from its lowest levels since 2004. The late surge is spearheaded by tech companies, while Janet Yellen pointed in her testimony that the path of interest rates will react partly to the developments of the financial markets. 

In a prepared testimony, Fed chairwoman yellen said that the bank still expects a gradual increase of interest rates this year, but signaled that a current tumult in financial markets could force the bank to delay or abandon its plans. 

Yellen pointed that the financial conditions in play now in the U.S. have become less supportive of growth, saying that if the current problems persist, it'd have an effect on the U.S. economic activity and the jobs sector. 

Wall Street was hammered from the beginning of the year as commodities cratered, impacted by a slowdown in China and a drop in global demand. The turmoil then hit the banking and tech sectors. 

S&P 500 jumped 0.76%, or 14.15 points to 1,866.36, while Dow Jones advanced 0.49%, or 78.14 points to 16,092. 

Tech-heavy NASDAQ climbed 1.60%, or 68.42 points to 4,337.18.