Wilfredo Lee, File, Associated Press
FILE - In this Thursday, Jan. 8, 2015, file photo, a "sale pending" sits atop a realty sign outside a home for sale in Surfside, Fla. The National Association of Realtors releases its September 2015 report on pending home sales on Thursday, Oct. 29, 2015.

WASHINGTON — September marked a slowdown in Americans signing contracts to buy homes, the second consecutive decline for a real estate market that has been rebounding for the first half of 2015.

The National Association of Realtors says its seasonally adjusted pending home sales index dropped 2.3 percent to 106.8 last month. The index has risen 3 percent over the past 12 months, aided by solid hiring levels and low mortgage rates.

But signs of fading momentum have surfaced in recent months. Sales of newly built homes fell 11.5 percent last month, as choppy financial markets and rising home prices are creating affordability pressures for would-be buyers.

Pending sales are a barometer of future purchases. A lag of a month or two usually exists between a contract and a completed sale.