Maybe it was just too good to last.

After four weeks of declining interest rates Freddie Mac reported a relatively sharp jump for each of the products it tracks during the week ended October 12.

Frank Nothaft, Freddie Mac's vice president and chief economist blamed inflation jitters for the spike, saying "Renewed concern that inflation is still an issue put some upward pressure on bond yields, which generally translates into higher interest and mortgage rates. ARM rates especially felt the weight of increased inflation fears, narrowing the gap between ARMs and fixed-rate mortgage rates. Thus, ARMs may become less desirable."

The details of the Primary Mortgage Market Survey are as follows:

The 30-year fixed-rate mortgage had an average contract interest rate of 6.37 percent with 0.5 points compared to 6.30 percent with 0.3 for the week ended October 5. One year ago the 30-year averaged 6.03 percent.

The 15-year fixed-rate mortgage increased 8 basis points to 6.06 percent and fees increased from 0.4 to 0.5. This is 44 basis points higher than the 15-year was the same week in 2005.

The Treasury-indexed 5/1 hybrid mortgage averaged 6.10 with 0.6 point. The previous week it was at 6.0 percent with 0.5 point and in mid October 2005 it averaged 5.57 percent.

One-year Treasury-indexed ARMs averaged 5.56 percent with 0.7 point, a jump of 10 basis points over the average the previous week. Points were unchanged. At this time last year the one-year ARM averaged 4.85 percent.

Rates were also up according to the Mortgage Bankers Association's Weekly Mortgage Applications Survey for the week ending October 13. The average contract interest rate for 30-year fixed-rate mortgages was 6.33 percent compared to 6.27 percent the previous week. Points, including the origination fee, increased from 1.08 to 1.15.

15-year fixed rate mortgages carried an average rate of 6.01 percent, up 2 basis points from one week earlier. Points, however, dropped from 1.11 to 1.08.

One-year ARMs increased from 5.88 percent to 5.94 percent with points inching up from 0.85 to 0.85.

All rates quoted are for 80 percent loan to value mortgage originations.

Mortgage application volume was down slightly from the week of October 6. 2.2 percent fewer applications were received on a seasonally adjusted bases and 2.3 percent on an unadjusted basis from that earlier week. The pace of applications was off 11.4 percent from the same week in 2005.

Refinancing as a share of all activity dropped from 46.4 percent to 45 percent between October 6 and October 13 and the share of adjustable rate mortgages continued to drop - down to 26.5 percent from 26.9 percent one week earlier.