Given the recent swift increase in 10-year US Treasury yields, mortgage rates jumped nearly 100 basis points from their April 2013 lows of about 3.5% to around 4.5% in July. This was due mostly to a recent statement by the Federal Reserve that they might consider tapering their bond purchases in the near future due to the economy "starting to show signs of improvement."

This rise in borrowing costs seems to have made investors nervous and caused bond prices to tumble as yields jumped higher. But the real story to watch is the share price of the homebuilders. They are poised to feel the brunt of this market fear.