For the first time in a year, local Realtors are reporting a decrease in their optimism about the state’s housing market and home prices.

In May, the Massachusetts Association of Realtors Realtor Market Index stood at 39.49, 18.98 percent higher than the 33.19 score recorded in May 2009,  but down 23.71 percent from the April 2010 score of 51.76.

April’s reading above 50 was the first time the score had reached the positive side of the scale in more than a year. Measured on a 100-point scale, a score of 50 is the midpoint between a "strong" (100 points) and a "weak" (0 points) market condition, MAR said.

May was the first month that Realtors reported a decrease in optimism about home prices since June 2009.

The Realtor Price Index was down 7.73 percent in May 2010 compared to the same time last year (to 38.38 in 2010 from 41.59 in 2009). On a month-to-month basis, the May index number was down 30.96 percent from the Home Sales Price Index number of 55.59 in April 2010.

"In the first month post-tax credit, Realtors are feeling the results of buyers and sellers catching their breath from all the activity of the first four months of the year," said 2010 MAR President Kevin Sears, broker/co-owner of Sears Real Estate in Springfield.  "We’ll be looking toward the ultimate incentive of low interest rates and more affordable pricing to build on the success of the market to date and move the index numbers back up."

When Realtor members were asked how they would describe their buyer/seller activity since the April 30 deadline for the homebuyer tax credit passed, 59 percent of respondents reported that buyer/seller activity "somewhat" decreased (39 percent) or "significantly" decreased (20 percent).  Thirty-two percent of respondents reported that activity had "remained the same", while 10 percent reported that activity "somewhat" increased (8 percent) or "significantly" increased (2 percent).