After rising for nine straight months, the number of homes listed for sale fell for the first time in October across many U.S. markets.

The supply of homes available for sale in 26 major metropolitan areas fell by an average 3.3% last month compared to the previous month, the first month-over-month decline since January, according to figures compiled by ZipRealty Inc., a real-estate brokerage firm based in Emeryville, Calif.

Inventory fell on a monthly basis in 22 of those markets. The figures include all single-family homes, condominiums and townhouses listed on local multiple-listing services in markets where the firm operates.

Nationally, inventories typically increase in October as sellers make one last push before the seasonal downturn in sales hits. Zelman & Associates, a research firm, says October listings have typically increased by 0.8% from September over the past 28 years.

Compared to one year ago, the October inventory in the 26 markets covered by ZipRealty was up 13%. Home sales have been at very low levels since buyer tax credits expired in the spring, and that led inventories to pile up this summer.

The decline could reflect the fact that some frustrated sellers are throwing in the towel and deciding to wait until next year in hopes that demand will firm up. Some banks have also stopped selling foreclosed properties in certain states, including Florida, as they take steps to correct document-handling errors.

In Orlando, for example, inventory fell by 6.4% in October, after five straight months of increases. Other large decreases came in Austin, Texas (down 7.6%); Denver (6.5%); and Seattle (6%).

Inventories increased in Southwestern markets, led by Las Vegas (up 3.7%); Tucson, Ariz. (1.7%); Los Angeles (1.6%) and Phoenix (1.4%).

California metros also posted the largest annual increases in housing inventory: San Diego was up 62% for the year, followed by San Francisco, up 53%.

Inventories are down for the year in three Florida markets—Orlando, Jacksonville, Miami—as well as Chicago and Charlotte.

Several cities have seen more than half of all homes listed for sale have had their prices cut at the end of October, including Jacksonville, Phoenix, Chicago, Baltimore, Boston, Tuscon and California’s Orange County.