U.S. financial markets were battered at the end of last week because of a dramatic sell-off of Treasury bonds. The yield on 10-year bonds which has been rising since May neared the critical barrier of 5.25% on June 8 -- the highest level in five years. Media reports suggest that turmoil in the bond market could continue this week making investors anxious about whether interest rates might go up and bring to an end the period of cheap money that has buoyed up asset markets and also funded a world-wide boom in mergers. Why are bond yields so high? What do these developments mean for stocks and other asset classes? Knowledge at Wharton discussed these questions with Jeremy Siegel a professor of finance at Wharton and author of The Future for Investors.