(Reuters) - D.R. Horton DHI.N shares fell more than 10 percent after the largest U.S. homebuilder forecast first-quarter home sales below analysts' estimates on Thursday, the latest sign that rising mortgage rates and higher home prices are weighing on the housing market.

FILE PHOTO: A house built by the D.R. Horton company is seen for sale in Arvada, Colorado January 24, 2017. REUTERS/Rick Wilking/File Photo

The weakness in shares also hit other homebuilders' stocks. PulteGroup PHM.N fell 6 percent, while Lennar LEN.N was down 4 percent.

The housing market has been a weak spot in a robust U.S. economy, with economists blaming the sluggishness on rising mortgage rates, which have combined with higher house prices, to make home purchasing unaffordable for some buyers.

“The buyer is probably affordably stretched and taking a little bit of time to reset to changing market environment,” D.R. Horton Chief Operating Officer Michael Murray said on a conference call with analysts.

The company said it was seeing a rise in incentive spending for homes priced $300,000 and above. These kinds of homes make up about a third of the company’s total deliveries.

The homebuilder said it expects incentives to increase in the face of the choppy demand environment and forecast full-year 2019 home sales gross margins to be in the range of 20 percent to 22 percent, with the midpoint below analysts’ estimate of 21.48 percent.

Demand is holding up in the less expensive category, but homebuilders have not been able to boost supplies as they have been held back by scarce labor, limited lot supplies and rising raw material costs.

Single-family homebuilding, which accounts for the largest share of the housing market, has lost momentum since hitting a pace of 948,000 units last November, which was the strongest in more than 10 years.

D.R. Horton said on Thursday it expects first-quarter home deliveries in the range of 11,000-11,500 units, below analysts’ average estimate of 11,852 homes, according to IBES data from Refinitiv.

The company, however, did not provide any details of its sales and profit expectations for 2019.

For the fourth quarter, the company’s revenue rose 8.3 percent to $4.51 billion, but fell just short of estimate of $4.57 billion.

The company’s net income rose 48.8 percent to $466.1 million, or $1.22 per share, in the fourth quarter ended Sept. 30, in line with analysts’ expectation.

The broader PHLX housing index .HGX, down 22.3 percent this year, fell another 3 percent.