Mortgage rates inch up

NEW YORK (CNNMoney.com) -- Home mortgage rates were slightly higher this week, jumping from near record-lows last week, according to a report released Thursday.

The average 30-year fixed mortgage rate jumped to 5.23%, up from 5.18% the previous week, according to Bankrate.com's weekly national survey.

Even with the increase, rates remain at historic lows, the report said. Rates have plunged since late October, when 30-year fixed home mortgage rates averaged 6.77%.

"Mortgage rates have been comparatively tame in recent weeks, but one exception has been the jumbo mortgage market," the report said.

Jumbo loans are considered too large to be purchased or guaranteed by Fannie Mae (FNM, Fortune 500) and Freddie Mac (FRE, Fortune 500), and they carry higher rates than smaller "conforming" loans that do carry guarantees.

"[Mortgage] rates are still higher than they would be in a normal credit environment, but with the slowly thawing credit markets the spread between conforming and jumbo rates has narrowed to levels last seen in Nov. 2008," the report said.

Six months ago, the average 30-year fixed mortgage rate was 6.32%, meaning a $200,000 loan would have carried a monthly payment of $1,240.55. With the average rate now at 5.23%, the monthly payment for the same size loan would be $1,101.93, meaning homeowners who refinance now would save more than $140 per month.

Other rates: The average 15-year fixed rate mortgage ticked up to 4.75% from 4.72% the week prior.

The average jumbo 30-year fixed rate dropped sharply to 6.52% from 6.69% the week prior.

Adjustable rate mortgages were "all over the map," the report said, with the average 1-year ARM rising to 5.32% while 5/1 ARMs fell to 5.11%.