Pending home sales fell 4.3% to an index reading of 101.7 in December, after a downwardly revised 1.6% increase to 106.3 in November, according to a report released Monday by the National Association of Realtors.
Economists polled by Thomson Reuters predicted that the index would be up 0.3%.
November's rise was initially reported as 1.7% to 106.4.
An index of 100 is equal to the average level of contract activity during 2001.
Year-over-year the pending homes sales index is up 6.9% from last December, when the index was 95.1.
Regionally, pending sales were mostly lower. The Northeast saw a 5.4% decrease to 78.8, while sales rose 0.9% in the Midwest to 104.8. In the South, sales fell 4.5% to 111.5, and sales slid 8.2% to 101.0 in the West.
"The supply limitation appears to be the main factor holding back contract signings in the past month. Still, contract activity has risen for 20 straight months on a year-over-year basis," NAR Chief Economist Lawrence Yun said. "Buyer interest remains solid, as evidenced by a separate Realtor survey which shows that buyer foot traffic is easily outpacing seller traffic."