Single-family home prices nationwide were unchanged in May, the first time in nearly a year they have not fallen on a monthly basis, though prices were still down compared to a year earlier, a closely watched survey said on Tuesday.

The S&P/Case Shiller composite index of home prices in 20 metropolitan areas held steady on a seasonally adjusted basis and in line with economists’ expectations, according to a Reuters poll.

The last time the seasonally adjusted index rose month-over-month was in June 2010, shortly after the homebuyer tax credit expired.

On a non-seasonally adjusted basis, the index rose 1 percent, the second month of gains in a row, the report said.

"This is a seasonal period of stronger demand for houses, so monthly price increases are to be expected," David Blitzer, chairman of the index committee at Standard & Poor’s, said in a statement. "The concern is that much of the monthly gains are only seasonal."

Prices in the 20 cities fell 4.5 percent year-over-year, which was also in line with forecasts.

Meanwhile, another report found new single-family home sales nationwide unexpectedly fell in June while national median prices rose 7.2 percent to $235,000 in June from a year ago.

The Commerce Department said sales fell 1 percent to a seasonally adjusted 312,000-unit annual rate as sales in the Northeast tumbled to a record low. Sales were also pulled down by a sharp drop in the West. May’s sales pace was revised down to 315,000 units from the previously reported 319,000 units.

The rise in prices is the latest hopeful sign that home values are starting to stabilize.

Data last week showed the median price of an existing home increased 0.8 percent to $184,300 from June last year.

Economists polled by Reuters had forecast sales at a 320,000-unit rate. In the 12 months through June, new home sales rose 1.6 percent.

Despite lean inventories, recovery in the market for new homes is being frustrated by a glut of previously owned homes, which are currently selling well below the cost of new construction.

There were a record low 164,000 new homes available for sale in June. That compares to about 3.77 million used homes on the market in June, plus properties that are in foreclosure.

The scarcity of new homes is encouraging builders to break ground on new projects. Data last week showed housing starts rose to a six-month high in June.

At June’s sales pace, the supply of new homes on the market fell to 6.3 months’ worth, the lowest since April 2010, from 6.4 months’ worth in May.