No Free Lunch in Closed-End Funds 

A good article above by Barron's last weekend. 

Can you believe that many high income bond funds are trading 20% to 70% above the NAV? 66% of taxable bond funds and 73% of municipal-bond funds trade above NAV now versus roughly 30% both a year ago and in 2006. 

Investor sentiment could shift, sending shares tumbling. Any hint of rising interest rates would be a concern, as would expectations that the gap between short- and long-term rates might narrow. That would hurt funds relying on short-term borrowing to buy long-term assets.