The number of single-family homes put under agreement in December was up 5 percent over the same time last year, while condominiums were up 26 percent, according to the Massachusetts Association of Realtors (MAR).

December marks the sixth straight month the number of homes put under agreement had increased over the year before, according to MAR.

"It is a positive sign to see that pending sales went up each month in the second half of the year as the real estate market is showing signs of improvement," said 2010 MAR President Kevin Sears, broker/co-owner of Sears Real Estate in Springfield. "Now with the extension and expansion of the homebuyer tax credit until April 30, we should see this trend continue over the winter months, a traditionally slower time for home sales."

There were 2,743 single-family homes put under agreement in December, up from 2,615 homes in 2008. On a month-to-month basis, single-family homes put under agreement were down 19 percent from 3,387 homes in November.

There were 1,248 condos put under agreement in December, up from 922 units in 2008. On a month-to-month basis, condos put under agreement were down 9.4 percent from 1,379 units in October.

The tracking of signed purchase and sales agreements, or pending sales, provide reliable information about where the real estate market is heading in coming months.