Investors have been taking a greater interesting in housing with rates and prices at historical lows.

Record-low mortgage rates and the most affordable housing market in 20 years are jump-starting investments in the mortgage markets, though financing remains tricky.

Last week, the 30-year FRM fell to 4.01 percent, the lowest rate in the history of Freddie Mac’s records, and in some spots in California, rates were down to 3.90 percent. 15-year FRMs are at similarly fantastic levels, coming in at 3.28 percent.

And investors are responding with pizzaz; they accounted for 22 percent of existing home sales in August, a 4 percent increase from July, and the Mortgage Bankers Association’s purchase index rose 2.6 percent in its latest survey.

Yet, even with the investment environment strong, financing remains tough, and investors have resorted to cash purchases to acquire properties. In August and July, cash purchases were 29 percent of sales, according to the National Association of Realtors, continuing a trend from 2010. In August 2010, cash purchases were 28 percent of home sales.