What started in the subprime mortgage bond market earlier this year is filtering into the broader credit markets, but the nervousness is less a sign of deteriorating credit quality--defaults are at historic lows of 0.3%, according to Coffey--and more an oversupply issue.

FORBES: Crunch Time

Bank of China's interest in securitization coincides with an unprecedented start to the year for the commercial-mortgage-bond market.

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

Like the mortgage market, the municipal bond market has morphed into its own new era of highflying finance, adjustable-rate loans and complex securities.

FORBES: Beware The Son of Subprime

As you know, before the collapse of the mortgage-backed bond market in 2007, banks routinely offered mortgages worth more than 90% of the value of a house - and even 100% mortgages were relatively common.

BBC: Should the Treasury take housing risk?

But younger investors also might want to consider repaying at least some of their mortgage using money they otherwise would invest in bonds, simply because repaying the mortgage offers a higher rate of return than that available in the bond market.

WSJ: Upside: Pay Off That Mortgage Now!

The SPDR Barclays Capital Mortgage Backed Bond ETF ( MBG) seeks to provide investment results that, before fees and expenses, correspond generally to the price and yield performance of an index that tracks the U.S. agency mortgage pass-through sector of the U.S. investment grade bond market.

FORBES: Uncertainty Leads Bond ETFs Higher

Over the next month the bond market convulsed and investors fled risky paper of the sort most mortgage REITs hold.

FORBES: Follow Through

When the Federal Reserve Open Market Committee met in June, more bond purchases to push down long-term Treasury and mortgage rates were already on the table.

FORBES: Bernanke is Bluffing