NEW YORK CITY—Home sale prices increased in May at their slowest pace in more than a year, S&P Dow Jones Indices said Tuesday. The S&P/Case-Shiller Home Price Indices rose 9.4% year-over-year for the 10-City Composite and 9.3% for the 20-City Composite, down significantly from the 10.9% and 10.8% increases reported last month. With the exception of Charlotte and Tampa, all 20 cities saw their annual rates decelerate.

“Housing has been turning in mixed economic numbers in the past few months,” says David M. Blitzer, chairman of the index committee at S&P Dow Jones Indices, who notes that May's numbers were the lowest since February 2013. “Prices and sales of existing homes have shown improvement while construction and sales of new homes continue to lag. At the same time, the broader economy and especially employment are showing larger improvements and substantial gains.”

Nine cities—Las Vegas, up 16.9%; San Francisco (15.4%), Miami (13.2%), San Diego (12.4%), Los Angeles (12.3%), Detroit (11.9%), Atlanta (11.2%), Tampa (10.2%) and Portland (10%)—posted double-digit increases in May. Regionally, Blitzer says, “The Sun Belt continues to lead with seven of the top eight performing cities. Eighteen of 20 cities had lower year-over-year numbers than last month; San Francisco and San Diego saw their year-over-year figures decelerate by about three percentage points.”

On a month-to-month basis, housing prices dropped for the first time in two years. Bloomberg reported Tuesday that the median projection of 30 economists surveyed had called for a 9.9% increase Y-O-Y.

Economists from IHS Global Insights have come to a similar conclusion as Societe Generale's Aneta Markowska, who told Bloomberg on Tuesday that a slower, more sustained growth rate was better for the market. “This time last year, prices began to grow at double-digit yearly rates; with this in mind, a smaller increase over a higher base is a healthy sign,” write Patrick Newport and Stephanie Karol, US economists with IHS. “Since home price appreciation is closely tied to the economic health of the cities covered in the index, this report suggests that home price growth is fueled by fundamentals, and not a speculative bubble.”