The yields on these long-dated bonds is already relatively low, in the 4% to max 6% range for investment grade debt.

FORBES: Brazil's Upgrade Doesn't Surprise Market; Watch for EWZ $80 Before Pullback

The Federal Reserve's low interest-rate policies have pushed more investors from relatively safer investments to those with higher yields and greater risks.

WSJ: Bank of China Eyes Expansion Into U.S. Securitization