Home sales in August increased 8.5% from one year ago and slightly higher than July, according to an estimate from real estate franchisor RE/MAX.

The report could signal continued improvement in existing home sales data from the National Association of Realtors scheduled for release Wednesday.

Home sales increased from one year ago for the 14th straight month in August, RE/MAX said.

The median sales price was $168,685, roughly flat from July but up 6.3% from last year on tighter inventory.

The amount of homes available for sale was 29.7% below levels last year and represented a 4.9 months supply. A six-month supply historically marks a balanced market for sellers and buyers.

"Nearly every month in 2012 experienced increased sales and prices over 2011, showing that we've definitely passed the bottom and we're looking forward to 2013 being an even better year," said RE/MAX CEO Margaret Kelly.

Of the 53 metro areas covered by the firm, 44 had an increase in sales from last year. And 29 have double-digit increases.

Activity increased 35.6% in Trenton, N.J. and more than 28% in Chicago, two of the largest gains in the country.