By Dan Weil The S&P; 500 has endured a negative return of 20% year to date, and the Bloomberg Aggregate bond index has dropped 11%. It obviously hasn’t been a very good six months for stocks or bonds. The S&P 500 has generated a negative return of 20% year to date, and the Bloomberg Aggregate bond index has slid 11%. That has some investors headed for the exits. For the week ended June 22, global equity funds suffered an outflow of $16.8 billion, with $17.4 billion coming out of the U.S. That means the rest of the world had inflow. The U.S. outflow was the first in seven weeks. The data comes …