Mortgage rates held steady Tuesday in volatile trading ahead of this morning’s Congressional testimony by Fed Chair Janet Yellen. In economic news, the January Producer Price Index (PPI) jumped 0.6%, well above the consensus forecast for an increase of 0.3%. Core PPI, which excludes volatile food and energy components, rose 0.4%, also above expectations, and was 1.2% higher than one year ago. Fed Chairwoman Yellen will deliver her semi-annual testimony to Congress at 10:00 AM.