Adds background, details from the conference call and updates shares

By Abhinav Parmar

Jan 21 (Reuters) - U.S. homebuilder D.R. Horton DHI.N topped analysts' estimates for first-quarter results on Tuesday, helped by incentives and favorable housing demand.

Shares of the company, which rose more than 5% before the bell, pared gains and were down about 1% in afternoon trading.

Arlington, Texas-based D.R. Horton has offered incentives such as mortgage rate buydowns - permanent or temporary interest-rate reductions on home loans to mitigate customer worries about high interest rates - while also offering smaller homes.

"Despite continued affordability challenges and competitive market conditions, incentives such as mortgage rate buydowns have helped to address affordability and spur demand," D.R. Horton Executive Chairman David Auld said.

It expects incentive costs to increase on homes closed over the next few months and home sales gross margin to be lower in the second quarter on a sequential basis, the company said in a post-earnings call.

It reported a gross margin of 22.7% for the first quarter ended Dec. 31, below the 22.9% it posted a year ago.

The largest U.S. homebuilder by revenue closed sales on 19,059 homes in the reported quarter, down 1% from 19,340 homes a year earlier.

"We're hopeful that they're able to do some things that will help drive affordability," COO Michael Murray said, when asked about the potential impact of tariff and immigration policy under U.S. President Donald Trump's administration.

The company posted first-quarter revenue of $7.61 billion, above analysts' average estimate of $7.08 billion, according to data compiled by LSEG.

Its earnings of $2.61 per share for the quarter were also above analysts' estimates of $2.36 per share.

(Reporting by Kannaki Deka and Abhinav Parmar in Bengaluru; Editing by Tasim Zahid and Pooja Desai)

((Kannaki.Deka@thomsonreuters.com))