NEW YORK ( RateWatch) -- The Credit Power Index, which measures the interest rate climate for American consumers, declined by 24 basis points in March -- the largest one-month improvement in the index since June.

It's the fourth straight month the index has dropped, offering clear evidence of a recovery in consumer interest rates after a late 2010 spike threatened to reverse the trend of the past two years. As of the end of March, the index stands at 23.3; while that's still up considerably over pre-recession levels (four years ago the index was at 19.21), it still marks an improvement over the peak of 25.46 reached at the height of the recession in May 2009.

The Credit Power Index is calculated by comparing the gap between certificate of deposit rates at four terms -- 12, 36, 48 and 60 months -- with the rates on selected loan products at the same terms (personal unsecured loans, home equity loans, new auto loans and adjustable-rate mortgages). The larger the disparity between loan and deposit rates, the higher the index will be, indicating how much consumers are getting squeezed by their banks. (See our graphic for a full explanation of the methodology.)

In March all of the good news came on the loan side of the equation, with loan rates dropping 29 basis points in the aggregate.

"The loan component on the national level is the lowest it has been since we started tracking this indicator in January of 2007," notes RateWatch Chief Operating Officer Bob Quinn. "In fact, the loan component back in January of 2007 was 25% higher than the current value."

Home equity loans stayed relatively stable and auto and personal unsecured loans saw modest drops, but the big story here is five-year adjustable-rate mortgages, which fell 15 basis points between February and March to 3.73%. Average rates for the product had been on the rise since bottoming out at an astonishing 3.42% in October, but this latest dip suggests ARM rates will stay below 4% for the foreseeable future. In this respect rates reflect the home mortgage market as a whole, where 30-year fixed mortgages have held steady around 5% for months.

Unfortunately, deposit rates also continue to hold steady after showing some encouraging signs in February. CD rates fell five basis points in the aggregate last month, with 60-month CDs losing a point after spiking the preceding month. As of the end of March, the average 12-month CD now pays out just 0.52% -- a new low -- and there are few signs that rates are going to turn around anytime soon.

On a regional level, Quinn says, the South boasted the most consumer-friendly rates in the country for the second straight month, while the West once again had the worst rates in the U.S., a dubious distinction it has held for more than two years.

"This is primarily due to the Southern region paying substantially higher returns for deposit products," Quinn says.

March also brought the usual month-to-month variance on the regional level. The central region, for instance, dropped 21 basis points after spiking 31 basis points the preceding months. In general such month-to-month regional swings can be disregarded as statistical noise, though it's worth noting that the East has fallen consistently for the past three months and the West fell 84 basis points during the same period. While it's not clear whether these regional trends will continue, for now we can at least say that the country as a whole continues to move in a direction that's benefiting consumers.

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